The document summarizes research on stress distribution in soils under the pile cap of tapered piles in compressible clay. Laboratory tests were conducted using modeled tapered piles in compressible clay from Belarus. Field tests measured stresses in soils at different depths under loaded pile caps connected to instrumented tapered piles installed in compressible clay. Results found stresses slightly higher than calculated using Boussinesq's theory. Stresses increased towards pile centers and with depth, and were directed along radius vectors from pile centers. Stresses decreased radially outward from pile centers and with increased pile spacing. Stress distribution was also affected by pile spacing and tapering angle. Clearly delineated stressed zones of soil deformation were observed under loaded pile caps.
This document summarizes research comparing the design of isolated footings in cohesive soils versus non-cohesive soils. Standard penetration tests were conducted in both soil types to determine their bearing capacities. Footings were then designed for a sample load of 500kN applied to a column. For cohesive soil, the designed footing was 2.5m x 2.5m x 0.205m, while for non-cohesive soil it was 1.9m x 1.9m x 0.201m. The volume and cost of the footing is 56.25% higher for cohesive soil. Therefore, for the same applied load, isolated footings are more economical in non-cohesive soils. For co
This document provides an overview of soils investigation and foundation design. It discusses the importance of soils investigation to evaluate subsurface conditions for construction projects. Various field and laboratory techniques are described for soils investigation, including test pits, boreholes, geophysical methods, and laboratory analysis. Factors influencing soil formation such as weathering and transportation are also covered. The document then discusses shallow foundation design, including bearing capacity theory, settlement analysis, and selection of appropriate foundation types based on subsurface conditions. Specific foundation types like spread footings, raft foundations, and their analysis are summarized.
This document summarizes a study on modeling negative friction forces on pile foundations in loess soils prone to consolidation. It discusses European and Ukrainian design standards, previous research, and a case study modeling test pile behavior using PLAXIS 3D Foundation software. The study aims to clarify methods for incorporating negative skin friction forces resulting from soil consolidation, which can reduce pile capacity. Numerical modeling is seen as a way to better understand pile-soil interaction and deformation over time compared to physical testing alone.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
This document presents a case study on estimating the modulus of subgrade reaction (k-value) for designing raft foundations of multi-story buildings constructed on sandy soil in Dammam, Saudi Arabia. Site investigations including boreholes and plate load tests were conducted. Plate load tests were back analyzed using numerical modeling to validate the soil properties. Different sized foundations were then modeled to estimate k-values. The k-values decreased with increasing foundation size and sometimes differed from values estimated using Terzaghi's equation, highlighting that k-value depends on foundation properties and soil conditions.
1) The document discusses the effect of replacing soil with more competent granular fill materials like mixtures of 6mm metal and sand.
2) Direct shear tests were conducted on mixtures of white metal, black metal, and sand in various proportions. The tests showed that angle of internal friction increases with higher percentages of metal, with the 2:1 and 3:1 metal to sand ratios providing the best strength.
3) One dimensional compression tests were also conducted by replacing soil with the granular fill materials. The tests showed the granular materials have a much higher initial coefficient of subgrade reaction, indicating greater stiffness compared to the soils tested.
This document discusses different types of shallow foundations including cantilever footings, combined footings, and mat foundations. It provides details on:
1. The design process for cantilever footings which involves iterative calculations to determine reactions and footing sizes to achieve uniform soil pressure.
2. Factors that influence the choice of foundation type including soil bearing capacity and building layout.
3. Design considerations for mat foundations on sand and clay soils including allowable bearing pressures.
This document summarizes research comparing the design of isolated footings in cohesive soils versus non-cohesive soils. Standard penetration tests were conducted in both soil types to determine their bearing capacities. Footings were then designed for a sample load of 500kN applied to a column. For cohesive soil, the designed footing was 2.5m x 2.5m x 0.205m, while for non-cohesive soil it was 1.9m x 1.9m x 0.201m. The volume and cost of the footing is 56.25% higher for cohesive soil. Therefore, for the same applied load, isolated footings are more economical in non-cohesive soils. For co
This document provides an overview of soils investigation and foundation design. It discusses the importance of soils investigation to evaluate subsurface conditions for construction projects. Various field and laboratory techniques are described for soils investigation, including test pits, boreholes, geophysical methods, and laboratory analysis. Factors influencing soil formation such as weathering and transportation are also covered. The document then discusses shallow foundation design, including bearing capacity theory, settlement analysis, and selection of appropriate foundation types based on subsurface conditions. Specific foundation types like spread footings, raft foundations, and their analysis are summarized.
This document summarizes a study on modeling negative friction forces on pile foundations in loess soils prone to consolidation. It discusses European and Ukrainian design standards, previous research, and a case study modeling test pile behavior using PLAXIS 3D Foundation software. The study aims to clarify methods for incorporating negative skin friction forces resulting from soil consolidation, which can reduce pile capacity. Numerical modeling is seen as a way to better understand pile-soil interaction and deformation over time compared to physical testing alone.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
This document presents a case study on estimating the modulus of subgrade reaction (k-value) for designing raft foundations of multi-story buildings constructed on sandy soil in Dammam, Saudi Arabia. Site investigations including boreholes and plate load tests were conducted. Plate load tests were back analyzed using numerical modeling to validate the soil properties. Different sized foundations were then modeled to estimate k-values. The k-values decreased with increasing foundation size and sometimes differed from values estimated using Terzaghi's equation, highlighting that k-value depends on foundation properties and soil conditions.
1) The document discusses the effect of replacing soil with more competent granular fill materials like mixtures of 6mm metal and sand.
2) Direct shear tests were conducted on mixtures of white metal, black metal, and sand in various proportions. The tests showed that angle of internal friction increases with higher percentages of metal, with the 2:1 and 3:1 metal to sand ratios providing the best strength.
3) One dimensional compression tests were also conducted by replacing soil with the granular fill materials. The tests showed the granular materials have a much higher initial coefficient of subgrade reaction, indicating greater stiffness compared to the soils tested.
This document discusses different types of shallow foundations including cantilever footings, combined footings, and mat foundations. It provides details on:
1. The design process for cantilever footings which involves iterative calculations to determine reactions and footing sizes to achieve uniform soil pressure.
2. Factors that influence the choice of foundation type including soil bearing capacity and building layout.
3. Design considerations for mat foundations on sand and clay soils including allowable bearing pressures.
1) The document discusses the behavior of laterally loaded vertical and batter piles used as deep foundations. It describes Winkler's hypothesis which models soil-pile interaction using independent springs.
2) It presents the differential equation that governs the deflection of laterally loaded piles, involving terms for deflection, slope, moment, shear, and soil reaction. The equation is solved using p-y curves which model the nonlinear soil-pile interaction.
3) It summarizes previous research on model and field tests of vertical and batter piles under lateral loads. Batter piles are used to resist higher horizontal loads than vertical piles alone. The research provides data to develop solutions for analyzing laterally loaded pile behavior.
Effect of vertical cross sectional shape of foundation and soil reinforcementIAEME Publication
This document discusses an experimental study on the effect of vertical cross-sectional shape of foundations and soil reinforcement on the settlement and bearing capacity of soils. Models of shallow foundations with rectangular, wedge, and T-shaped vertical cross-sections were tested on both unreinforced and reinforced soft clay soils. The study found that soil reinforcement under foundations reduces settlement and increases bearing capacity. Foundations with rectangular cross-sections had higher bearing capacity ratios than those with wedge or T-shaped cross-sections.
This document summarizes a study that analyzed the performance of vertical skirted strip footings on slopes using the finite element software PLAXIS 2D. Various parameters were considered, including the vertical load, depth of footing embedment, distance of footing from crest, ratio of skirt depth to footing width, and configuration of the skirt (one side, both sides, unequal sides). The results showed that skirted foundations significantly improved the bearing capacity compared to unskirted foundations. Bearing capacity increased with deeper skirt depths. Footings at the crest also showed improved bearing capacity. Footing embedment depth did not affect bearing capacity. The study provides insights into using skirted foundations to improve slope stability and bearing capacity
The document discusses determining the active earth thrust on fascia retaining walls through theoretical and experimental methods. Fascia retaining walls are constructed in front of existing structures in narrow spaces. Model experiments were conducted to measure deflections under different aspect ratios (the ratio of backfill width to wall height). Earth thrust was calculated using the theoretical equation and compared to values obtained experimentally. The experimental results showed good agreement with the theoretical values, with differences of less than 5% for most tests. It was concluded that the proposed theoretical method can be reliably used to design fascia retaining walls.
Experimental estimate of ultimate bearing capacity and settlement for rectangIAEME Publication
The document summarizes experimental tests conducted to estimate the ultimate bearing capacity and settlement of rectangular footings on sand. Laboratory model tests were performed on footings with varying sizes (100mm x 125mm, 100mm x 150mm, etc.) and a constant depth of sand cushion below the footing of 900mm. The tests measured how loading intensity affected settlement. Log-load vs log-settlement curves were plotted from the results, and the point of intersection was used to determine ultimate bearing capacity and corresponding settlement. Bearing capacity factors were computed and compared to theoretical values. The tests found that as footing size increased, ultimate bearing capacity and settlement values also increased, while the bearing capacity factor decreased.
This document discusses soil improvement techniques for foundations. It describes mechanical compaction as the least expensive method, which involves removing weak soil and refilling/replacing it in layers with compaction. Two common compaction tests are described - the Standard Proctor Test and Modified Proctor Test - which involve compacting soil in a mold to determine the optimum moisture content and maximum dry density. Factors like moisture content and compactive effort influence compaction results.
This document discusses foundation settlement, including definitions, types of settlement, factors that influence settlement, and permissible settlement limits. It begins with definitions of key settlement terms like maximum settlement, differential settlement, and angular distortion. It then describes the three main types of settlement - immediate, consolidation, and secondary - and factors that influence each type. The document provides guidance on permissible settlement from code IS 1904 and discusses methods to analyze and estimate settlement, including equations, test data interpretation, and settlement computation.
This document summarizes a laboratory testing program that investigated the time-dependent differential consolidation of slurry wall backfill material. Large-scale consolidation tests were performed on samples from an 11,000 m long, over 45 m deep slurry wall installed through glacial till. The results showed significant retardation of vertical stress in the backfill due to arching effects. Narrower trench widths led to greater loss of vertical effective stress. Differential consolidation around multiple aquifers crossed by the wall could increase due to the loss of vertical stress, potentially creating more permeable zones.
Bearing Capacity of High Density Polyethylene (HDPE) Reinforced Sand Using Pl...IJERA Editor
The work presented here is a study to examine the improvement in bearing capacity of coastal sand of Trivandrum, Kerala, India using high density polyethylene (HDPE) /woven fabric as reinforcement in discrete layers. The bearing capacity was evaluated using plate load test. The effect of reinforcement configurations like sheet reinforcement (sanded with adhesive, with adhesive and sheet alone) and strip reinforcement (single and grid pattern) are investigated. The test parameters chosen for the present study are, depth of topmost layer of reinforcement layer below footing, compacted density and number of layers of reinforcement etc. From the tests, it has been observed that sheet reinforcement is more effective than sheet sanded with adhesive and strip reinforcements. It is found that the synthetic adhesive gives no binding action at the interface of the reinforcement and soil. But it is to be noted that the sheet with adhesive dried has a marked influence on the bearing capacity especially at lower densities. The strip reinforcements in single pattern is considered to be a favorable choice for minimum reinforcement. The strip reinforcement in single or grid pattern gives sufficient improvement in strength.
UNDERSTANDING THE PERFORMANCE OF DEEP MIXED COLUMN IMPROVED SOILS - A REVIEWIAEME Publication
The essence of ground improvement is to enhance the engineering properties of weak soils to provide stability and sufficient bearing capacity for construction and other engineering purposes. Deep soil mixing is one method that has been widely employed for this purpose due to the
environmental nature and efficiency of this method. In deep soil mixing, the amount of binder to be mixed with the weak soil depends on the initial moisture content of the surrounding soil. Several researchers have reported on this method of soil improvement through laboratory experiments, in situ testing and numerical modelling.
A NUMERICAL STUDY ON INTERFERENCE EFFECTS OF CLOSELY SPACED STRIP FOOTINGS ON...IAEME Publication
Foundations of structures often need to be placed close to meet the architectural as well as the functional requirements. In such cases, the combined action of footings is different from a single footing. It causes interference of the stress zones. In the present study, the interference effects of two closely spaced strip footings on the surface of cohesive and cohesionless soils are being investigated. Parametric studies are done for two footings by varying the spacing between the footings and the width of the footings. The results are presented in terms of efficiency factors. In the first case, both the footings are loaded simultaneously up to failure. In the second case, one of the footings representing an already existing foundation is loaded with half of the estimated failure load of isolated footing and adjacent footing loaded up to failure. The effect of interference is observed to be particularly significant in terms of the settlement. Effect of shear keys placed beneath the footings, at different locations beneath the footing and the interference of such footings is also studied in case of stiff clay. It is found that the presence of shear keys has a significant effect on the interference between the footings, compared to without the shear keys, especially in reducing the tilt of foundations.
A review-effect-of-geo-grid-reinforcement-on-soilIjcem Journal
This document reviews research on using geo-grid reinforcement to improve weak soils for construction purposes. It first discusses how expansive soils like black cotton soil undergo failure due to moisture changes, making them poor for construction. Researchers have studied stabilizing such soils using additives or replacing the soil. Geo-grids are another option, as they can improve soil engineering properties through frictional interaction. The document then reviews several studies that found geo-grid reinforcement can increase soil bearing capacity and reduce pavement damage on expansive soils by preventing rutting and lateral movement.
1) Two approaches are used to determine the safe bearing pressure of soil: allowable bearing pressure based on shear failure criteria, and safe bearing pressure based on settlement criteria.
2) Plate load tests can be used to estimate the safe bearing pressure that results in a given permissible settlement. Tests are conducted with plates of different sizes and the load-settlement data is used to calculate settlement of prototype foundations using empirical equations.
3) Housel's method involves conducting two plate load tests and solving equations involving load, plate area and perimeter to determine constants, which are then used to calculate load and size of a prototype foundation that results in the permissible settlement.
This document provides lecture notes on soil mechanics from Einstein College of Engineering. It covers the objectives of the soil mechanics course, which is to provide knowledge of engineering properties of soil. The document then outlines the topics that will be covered, including introduction to soil properties, soil water and flow, stress distribution and compression, shear strength, and slope stability. It lists reference textbooks and provides an in-depth section on soil classification systems, properties, particle size distribution, consistency limits, and the Indian Standard Soil Classification System.
The effect of soil improvement on foundation super structure designIAEME Publication
This document summarizes a study on the effects of soil improvement on raft and folded plate foundation design. The authors used Winkler and continuum modeling methods to analyze raft foundations with and without soil strength increases below high settlement areas. They found that localized soil improvement significantly reduced settlement and allowed for reductions in foundation and superstructure material requirements like concrete and steel reinforcement. Selectively increasing soil stiffness parameters like modulus of subgrade reaction (ks) and modulus of elasticity (E) provided benefits to both flat raft and folded plate foundation designs in terms of reduced settlement, moments, and reinforcement needs.
Effect of Molybdenum Disulphide on Physical Properties of Neodymium-Iron-Boro...IJMER
The present paper reports the effect of molybdenum disulfide (MoS2) on magnetic and
mechanical properties of neodymium iron boron (NdFeB) bonded magnet. Powder metallurgy process
has been used to prepare the test samples containing 0.0, 0.5, 1, 1.5 and 2 percentage of MoS2. Compact
and hardness tests have been performed to measure the physical properties of samples. Saturation
magnetization, remanence and intrinsic coercivity have been checked using vibrating sample
measurement (VSM) test
1) The document discusses numerical modeling to determine negative friction forces on pile side surfaces during static load testing in settling soils. It presents modeling of single piles and pile clusters to approximate these forces.
2) Key findings from the modeling include that negative friction forces depend on the soil saturation case, soaked layer depth, and soil properties. Soaking from parallel settling layers below poses more risk than top soaking.
3) The proposed simplified modeling method allows preliminary analysis of pile behavior in loose settling soils under self-weight, accounting for negative friction forces with sufficient accuracy for design. Modeling results were confirmed in a construction project.
Evaluation of cbr using geosynthetics in soil layerseSAT Journals
Abstract In urban areas, the service life of pavement on weaker soil subgrade affected severely due to their high compressibility and plasticity behaviour. These soils possess less strength, CBR value and have high affinity to moisture content. Also the seasonal changes affects the soil properties adversely. Stabilization techniques using geo-synthetic materials for improving properties of these types of soft subgrades. To increase the sub grade soil strength and to reduce the thickness of flexible pavement, Geo-synthetics are increasingly used in wide variety of civil engineering applications. Geo- synthetics are the cost-effective ground modification materials which acts as a reinforcement and also increases the stability and bearing capacity of soil. Many researchers recommends the use of geo-synthetic material performs good results in soil stabilization. From this view, Evaluation has been made on poorly graded sand with the inclusion of go-grid, geo-textile and geo-composite materials between soil layers in different proportions. The CBR and shear parameters are determined for different combinations of subgrade thickness. The geo-engineering properties such as Atterberg limits, grain size distribution, compaction characteristics, and CBR value of poorly graded sand were evaluated and reported. To get the maximum California bearing ratio (CBR), the present study is put forward to understand the strength change in the soil with the addition of geo-synthetic materials. Such a study would be helpful in material selection based on site condition and strength gain along with economy. Keywords: Geo-synthetics, CBR, Strength, Economy.
1. The bearing capacity of a foundation refers to the ability of the soil to carry the loads from structures placed on it without shear failure or excessive settlement.
2. Terzaghi's bearing capacity theory separates the failure zone under a foundation into triangular and radial shear zones, and considers the equilibrium of forces within these zones to calculate the ultimate bearing capacity.
3. The allowable bearing capacity is calculated by applying a safety factor to the ultimate capacity to avoid shear failure. Settlement criteria may further limit the allowable capacity.
This document discusses soil arching in granular soils. It begins with an introduction to soil arching and how it occurs when stress is transferred from yielding soil to rigid adjacent zones. It then discusses experimental evidence of arching from previous studies. Finally, it covers the mechanism of arching, factors that affect it, theories about arching stresses and shapes, and limit state analysis used to analyze arching.
1. The document discusses Karl Terzaghi's principle of effective stress, which states that the stress on a soil is equal to the total stress minus the pore water pressure.
2. It then provides objectives and scope for a case study on evaluating Terzaghi's theory through consolidation tests. Materials used include remolded soil samples from various locations.
3. The document outlines Terzaghi's assumptions for his consolidation theory and provides his equations for calculating bearing capacity of strip, square, and circular footings. It also briefly reviews several literature sources analyzing consolidation and settlement prediction.
1) The document discusses the behavior of laterally loaded vertical and batter piles used as deep foundations. It describes Winkler's hypothesis which models soil-pile interaction using independent springs.
2) It presents the differential equation that governs the deflection of laterally loaded piles, involving terms for deflection, slope, moment, shear, and soil reaction. The equation is solved using p-y curves which model the nonlinear soil-pile interaction.
3) It summarizes previous research on model and field tests of vertical and batter piles under lateral loads. Batter piles are used to resist higher horizontal loads than vertical piles alone. The research provides data to develop solutions for analyzing laterally loaded pile behavior.
Effect of vertical cross sectional shape of foundation and soil reinforcementIAEME Publication
This document discusses an experimental study on the effect of vertical cross-sectional shape of foundations and soil reinforcement on the settlement and bearing capacity of soils. Models of shallow foundations with rectangular, wedge, and T-shaped vertical cross-sections were tested on both unreinforced and reinforced soft clay soils. The study found that soil reinforcement under foundations reduces settlement and increases bearing capacity. Foundations with rectangular cross-sections had higher bearing capacity ratios than those with wedge or T-shaped cross-sections.
This document summarizes a study that analyzed the performance of vertical skirted strip footings on slopes using the finite element software PLAXIS 2D. Various parameters were considered, including the vertical load, depth of footing embedment, distance of footing from crest, ratio of skirt depth to footing width, and configuration of the skirt (one side, both sides, unequal sides). The results showed that skirted foundations significantly improved the bearing capacity compared to unskirted foundations. Bearing capacity increased with deeper skirt depths. Footings at the crest also showed improved bearing capacity. Footing embedment depth did not affect bearing capacity. The study provides insights into using skirted foundations to improve slope stability and bearing capacity
The document discusses determining the active earth thrust on fascia retaining walls through theoretical and experimental methods. Fascia retaining walls are constructed in front of existing structures in narrow spaces. Model experiments were conducted to measure deflections under different aspect ratios (the ratio of backfill width to wall height). Earth thrust was calculated using the theoretical equation and compared to values obtained experimentally. The experimental results showed good agreement with the theoretical values, with differences of less than 5% for most tests. It was concluded that the proposed theoretical method can be reliably used to design fascia retaining walls.
Experimental estimate of ultimate bearing capacity and settlement for rectangIAEME Publication
The document summarizes experimental tests conducted to estimate the ultimate bearing capacity and settlement of rectangular footings on sand. Laboratory model tests were performed on footings with varying sizes (100mm x 125mm, 100mm x 150mm, etc.) and a constant depth of sand cushion below the footing of 900mm. The tests measured how loading intensity affected settlement. Log-load vs log-settlement curves were plotted from the results, and the point of intersection was used to determine ultimate bearing capacity and corresponding settlement. Bearing capacity factors were computed and compared to theoretical values. The tests found that as footing size increased, ultimate bearing capacity and settlement values also increased, while the bearing capacity factor decreased.
This document discusses soil improvement techniques for foundations. It describes mechanical compaction as the least expensive method, which involves removing weak soil and refilling/replacing it in layers with compaction. Two common compaction tests are described - the Standard Proctor Test and Modified Proctor Test - which involve compacting soil in a mold to determine the optimum moisture content and maximum dry density. Factors like moisture content and compactive effort influence compaction results.
This document discusses foundation settlement, including definitions, types of settlement, factors that influence settlement, and permissible settlement limits. It begins with definitions of key settlement terms like maximum settlement, differential settlement, and angular distortion. It then describes the three main types of settlement - immediate, consolidation, and secondary - and factors that influence each type. The document provides guidance on permissible settlement from code IS 1904 and discusses methods to analyze and estimate settlement, including equations, test data interpretation, and settlement computation.
This document summarizes a laboratory testing program that investigated the time-dependent differential consolidation of slurry wall backfill material. Large-scale consolidation tests were performed on samples from an 11,000 m long, over 45 m deep slurry wall installed through glacial till. The results showed significant retardation of vertical stress in the backfill due to arching effects. Narrower trench widths led to greater loss of vertical effective stress. Differential consolidation around multiple aquifers crossed by the wall could increase due to the loss of vertical stress, potentially creating more permeable zones.
Bearing Capacity of High Density Polyethylene (HDPE) Reinforced Sand Using Pl...IJERA Editor
The work presented here is a study to examine the improvement in bearing capacity of coastal sand of Trivandrum, Kerala, India using high density polyethylene (HDPE) /woven fabric as reinforcement in discrete layers. The bearing capacity was evaluated using plate load test. The effect of reinforcement configurations like sheet reinforcement (sanded with adhesive, with adhesive and sheet alone) and strip reinforcement (single and grid pattern) are investigated. The test parameters chosen for the present study are, depth of topmost layer of reinforcement layer below footing, compacted density and number of layers of reinforcement etc. From the tests, it has been observed that sheet reinforcement is more effective than sheet sanded with adhesive and strip reinforcements. It is found that the synthetic adhesive gives no binding action at the interface of the reinforcement and soil. But it is to be noted that the sheet with adhesive dried has a marked influence on the bearing capacity especially at lower densities. The strip reinforcements in single pattern is considered to be a favorable choice for minimum reinforcement. The strip reinforcement in single or grid pattern gives sufficient improvement in strength.
UNDERSTANDING THE PERFORMANCE OF DEEP MIXED COLUMN IMPROVED SOILS - A REVIEWIAEME Publication
The essence of ground improvement is to enhance the engineering properties of weak soils to provide stability and sufficient bearing capacity for construction and other engineering purposes. Deep soil mixing is one method that has been widely employed for this purpose due to the
environmental nature and efficiency of this method. In deep soil mixing, the amount of binder to be mixed with the weak soil depends on the initial moisture content of the surrounding soil. Several researchers have reported on this method of soil improvement through laboratory experiments, in situ testing and numerical modelling.
A NUMERICAL STUDY ON INTERFERENCE EFFECTS OF CLOSELY SPACED STRIP FOOTINGS ON...IAEME Publication
Foundations of structures often need to be placed close to meet the architectural as well as the functional requirements. In such cases, the combined action of footings is different from a single footing. It causes interference of the stress zones. In the present study, the interference effects of two closely spaced strip footings on the surface of cohesive and cohesionless soils are being investigated. Parametric studies are done for two footings by varying the spacing between the footings and the width of the footings. The results are presented in terms of efficiency factors. In the first case, both the footings are loaded simultaneously up to failure. In the second case, one of the footings representing an already existing foundation is loaded with half of the estimated failure load of isolated footing and adjacent footing loaded up to failure. The effect of interference is observed to be particularly significant in terms of the settlement. Effect of shear keys placed beneath the footings, at different locations beneath the footing and the interference of such footings is also studied in case of stiff clay. It is found that the presence of shear keys has a significant effect on the interference between the footings, compared to without the shear keys, especially in reducing the tilt of foundations.
A review-effect-of-geo-grid-reinforcement-on-soilIjcem Journal
This document reviews research on using geo-grid reinforcement to improve weak soils for construction purposes. It first discusses how expansive soils like black cotton soil undergo failure due to moisture changes, making them poor for construction. Researchers have studied stabilizing such soils using additives or replacing the soil. Geo-grids are another option, as they can improve soil engineering properties through frictional interaction. The document then reviews several studies that found geo-grid reinforcement can increase soil bearing capacity and reduce pavement damage on expansive soils by preventing rutting and lateral movement.
1) Two approaches are used to determine the safe bearing pressure of soil: allowable bearing pressure based on shear failure criteria, and safe bearing pressure based on settlement criteria.
2) Plate load tests can be used to estimate the safe bearing pressure that results in a given permissible settlement. Tests are conducted with plates of different sizes and the load-settlement data is used to calculate settlement of prototype foundations using empirical equations.
3) Housel's method involves conducting two plate load tests and solving equations involving load, plate area and perimeter to determine constants, which are then used to calculate load and size of a prototype foundation that results in the permissible settlement.
This document provides lecture notes on soil mechanics from Einstein College of Engineering. It covers the objectives of the soil mechanics course, which is to provide knowledge of engineering properties of soil. The document then outlines the topics that will be covered, including introduction to soil properties, soil water and flow, stress distribution and compression, shear strength, and slope stability. It lists reference textbooks and provides an in-depth section on soil classification systems, properties, particle size distribution, consistency limits, and the Indian Standard Soil Classification System.
The effect of soil improvement on foundation super structure designIAEME Publication
This document summarizes a study on the effects of soil improvement on raft and folded plate foundation design. The authors used Winkler and continuum modeling methods to analyze raft foundations with and without soil strength increases below high settlement areas. They found that localized soil improvement significantly reduced settlement and allowed for reductions in foundation and superstructure material requirements like concrete and steel reinforcement. Selectively increasing soil stiffness parameters like modulus of subgrade reaction (ks) and modulus of elasticity (E) provided benefits to both flat raft and folded plate foundation designs in terms of reduced settlement, moments, and reinforcement needs.
Effect of Molybdenum Disulphide on Physical Properties of Neodymium-Iron-Boro...IJMER
The present paper reports the effect of molybdenum disulfide (MoS2) on magnetic and
mechanical properties of neodymium iron boron (NdFeB) bonded magnet. Powder metallurgy process
has been used to prepare the test samples containing 0.0, 0.5, 1, 1.5 and 2 percentage of MoS2. Compact
and hardness tests have been performed to measure the physical properties of samples. Saturation
magnetization, remanence and intrinsic coercivity have been checked using vibrating sample
measurement (VSM) test
1) The document discusses numerical modeling to determine negative friction forces on pile side surfaces during static load testing in settling soils. It presents modeling of single piles and pile clusters to approximate these forces.
2) Key findings from the modeling include that negative friction forces depend on the soil saturation case, soaked layer depth, and soil properties. Soaking from parallel settling layers below poses more risk than top soaking.
3) The proposed simplified modeling method allows preliminary analysis of pile behavior in loose settling soils under self-weight, accounting for negative friction forces with sufficient accuracy for design. Modeling results were confirmed in a construction project.
Evaluation of cbr using geosynthetics in soil layerseSAT Journals
Abstract In urban areas, the service life of pavement on weaker soil subgrade affected severely due to their high compressibility and plasticity behaviour. These soils possess less strength, CBR value and have high affinity to moisture content. Also the seasonal changes affects the soil properties adversely. Stabilization techniques using geo-synthetic materials for improving properties of these types of soft subgrades. To increase the sub grade soil strength and to reduce the thickness of flexible pavement, Geo-synthetics are increasingly used in wide variety of civil engineering applications. Geo- synthetics are the cost-effective ground modification materials which acts as a reinforcement and also increases the stability and bearing capacity of soil. Many researchers recommends the use of geo-synthetic material performs good results in soil stabilization. From this view, Evaluation has been made on poorly graded sand with the inclusion of go-grid, geo-textile and geo-composite materials between soil layers in different proportions. The CBR and shear parameters are determined for different combinations of subgrade thickness. The geo-engineering properties such as Atterberg limits, grain size distribution, compaction characteristics, and CBR value of poorly graded sand were evaluated and reported. To get the maximum California bearing ratio (CBR), the present study is put forward to understand the strength change in the soil with the addition of geo-synthetic materials. Such a study would be helpful in material selection based on site condition and strength gain along with economy. Keywords: Geo-synthetics, CBR, Strength, Economy.
1. The bearing capacity of a foundation refers to the ability of the soil to carry the loads from structures placed on it without shear failure or excessive settlement.
2. Terzaghi's bearing capacity theory separates the failure zone under a foundation into triangular and radial shear zones, and considers the equilibrium of forces within these zones to calculate the ultimate bearing capacity.
3. The allowable bearing capacity is calculated by applying a safety factor to the ultimate capacity to avoid shear failure. Settlement criteria may further limit the allowable capacity.
This document discusses soil arching in granular soils. It begins with an introduction to soil arching and how it occurs when stress is transferred from yielding soil to rigid adjacent zones. It then discusses experimental evidence of arching from previous studies. Finally, it covers the mechanism of arching, factors that affect it, theories about arching stresses and shapes, and limit state analysis used to analyze arching.
1. The document discusses Karl Terzaghi's principle of effective stress, which states that the stress on a soil is equal to the total stress minus the pore water pressure.
2. It then provides objectives and scope for a case study on evaluating Terzaghi's theory through consolidation tests. Materials used include remolded soil samples from various locations.
3. The document outlines Terzaghi's assumptions for his consolidation theory and provides his equations for calculating bearing capacity of strip, square, and circular footings. It also briefly reviews several literature sources analyzing consolidation and settlement prediction.
This document summarizes research on the bearing capacity of sand overlying clay with a strip footing. Laboratory and numerical experiments were conducted to investigate the behavior and failure modes. Previous analytical methods for calculating bearing capacity are reviewed. The experimental setup involved testing isolated strip footings on a dense or loose sand layer overlying clay. Tests varied the sand layer thickness to footing width ratio and soil properties. Results presented failure modes, load-settlement curves, and relationships between bearing capacity and soil parameters.
Numerical simulation of laterally loaded pileDr. Naveen BP
This document presents a finite element model simulation of a lateral load test on a 1m diameter bored pile embedded in residual soils. The pile and soil were modeled in PLAXIS 2D, with the soil represented by a Mohr-Coulomb model and the pile as a beam element. The model results showed good agreement with load-displacement curves from the field test. However, the field test was unable to apply loads high enough to reach design code displacement limits due to limitations of test equipment for large piles in residual soils. The numerical model can simulate larger displacements to evaluate pile behavior under higher loads.
A Review Paper on Concrete Cast In-Situ Bored Piles Cushioned with Mixture of...IRJET Journal
This document reviews research on methods to improve the load carrying capacity of cast in situ concrete piles in clayey soil. It summarizes several studies that investigated using mixtures of sand and aggregate to cushion piles. Compacting the soil around test piles was found to increase friction and pile capacity by densifying the soil. Post-grouting piles after installation also increased bearing capacity by strengthening the soil-pile interface. Additional research found a linear relationship between the strength of cemented soil and the friction resistance at the interface between precast concrete piles and cemented soil. A new type of pile with a spray-expanded frustum was also developed and found to increase bearing capacity over 45% compared to conventional cast in situ piles due to improved skin
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
IRJET - Critical Appraisal on Footing Subjected to MomentIRJET Journal
This paper summarizes several studies on the moment capacity of foundations subjected to lateral loads, including experimental and numerical modeling work. Key findings include:
1) Centrifuge and numerical modeling show moment capacity increases with pier length, depth, and dense soil packing, but decreases with higher pier aspect ratios.
2) Experiments and modeling of pile groups and piled rafts found rafts increase lateral resistance over pile groups alone due to base contact pressure.
3) Testing of circular footings on clay found moment-rotation curves are nonlinear and moment limits increase with footing depth and width.
This document discusses bearing capacity theory and methods for determining the bearing capacity of soil. It defines key terms like maximum safe bearing capacity, allowable bearing pressure, and net pressure intensity. It describes different types of bearing capacity failure and assumptions in Terzaghi's bearing capacity method. The document also discusses other theories by Meyerhof, Vesic, and Skempton that improved on Terzaghi's method. Finally, it outlines field tests like plate load tests and laboratory tests to directly determine the bearing capacity of soil.
Triaxial test on soil important insights -formatted paperSamirsinh Parmar
This document discusses triaxial testing of soils under stress-controlled and strain-controlled loading modes. It provides a brief history of triaxial testing and describes key aspects of the test including the apparatus, sample preparation, procedures, and analysis of results. It explains that triaxial tests are useful for determining soil shear strength parameters and simulating three-dimensional stress conditions in the field. The document also summarizes important insights from previous studies comparing results of stress-controlled and strain-controlled triaxial tests.
This document discusses stress distribution in soil due to various types of loading. It begins by introducing key concepts like how applied loads are transferred through the soil mass, creating stresses that decrease in magnitude but increase in area with depth. The factors that affect stress distribution, like loading size/shape, soil type, and footing rigidity are also covered. The document then examines specific load types - point loads, line loads, rectangular/triangular strip loads, and circular loads - providing the equations to calculate vertical stress increases below each. Several examples demonstrate calculating stress increases below compound load arrangements. The summary provides an overview of the key topics and calculations presented in the document.
Behaviour of Single Pile in Reinforced Slope Subjected to Inclined Load IJERA Editor
This document summarizes an experimental investigation into the behavior of single piles in reinforced slopes subjected to inclined loading. Model tests were conducted with piles of varying length (10D and 20D) located near a 1V:2H sandy slope reinforced with layers of geogrid. The lateral load capacity of the piles was evaluated by applying loads laterally and at inclinations of 15° and 30°. The load capacity was found to increase with load inclination, pile length, number of geogrid layers, and distance from the slope crest. Load-deflection curves and ultimate lateral load capacities are presented for piles under different test conditions. The results provide insight into pile response based on parameters like reinforced slope design and loading angle.
Behaviour of Single Pile in Reinforced Slope Subjected to Inclined LoadIJERA Editor
Deep foundations, including driven piles, are used to support vertical loads of structures and lateral forces. Typical structures subjected to lateral loads include bridge abutments, transmission tower, sand offshore platforms. Traffic, wind, wave, and seismic forces are common types of lateral loads subjected to pile foundations. The present work is focused on understanding the lateral load capacity of vertical piles located near crest of the slope and subjected to the lateral and inclined loads. The experimental investigation was carried out to study the effect of reinforcing an earth slope on the inclined loading behavior of a single vertical pile located near the slope. Layers of geogrid were used to reinforce a sandy slope of 1V:2H. The parametric studies were performed by varying the length of pile(L), angle of inclination of load (θ), number of geogrid reinforcement (Nr) and crest distance. It was observed that the lateral load capacity of pile depends upon these parameters. The lateral load capacity of pile increases with increase in inclination of load, length of pile(L), number of geogrid reinforcement (Nr) and crest distance
Effect of Pile Length on the Settlement and Straining Actions for the pile Ra...IRJET Journal
The document summarizes a study on the effect of pile length on settlement and straining actions for pile raft foundations. Finite element analysis was used to model pile raft foundations with pile lengths of 28D, 32D, 36D, and 40D. The analysis found that as pile length increased from 28D to 40D:
1) The bending moment in the raft decreased by 29% under static and dynamic loads
2) The shear force in the raft decreased by 0.5% under static and dynamic loads
3) The settlement of the piled raft decreased by 40% under static and dynamic loads.
Field and Theoretical Analysis of Accelerated Consolidation Using Vertical Dr...inventionjournals
Mumbai is the region consisting of soft compressible marine clay deposits. There are several construction problems on such soils and thus ground improvement is need to be carried out. Vertical drains is generally preferred technique as accelerated settlement is achieved during the construction phase itself if planned accordingly. The concept of vertical drains is based on the theory of three dimensional consolidation as described by Terzaghi (1943). Based on this concept, a consolidation programme is developed and an attempt is made to determine the field to laboratory coefficient of vertical consolidation ratio by Taylor’s Square Root of Time Method and Casagrande’s Logarithm of Time Fitting Method for this region. Based on this, the rate of consolidation and time required for consolidation in the field can be determined knowing the consolidation parameters. Equations are developed by using output of the programme and it is explained.
Applicatio of Soil Structure Interaction in the analysis of flexible retainin...NikhilGautam68
Analysis and study of Soil Structure Interaction (ssi) in retaining wall. This presentation will help you in understanding the role of SSI in the making of a retaining wall which also expands the opportunity of research to great extent.
The main objectives are as follows:
1. To analyse the deformation of the structural system based on mobilised earth pressure and soil resistance along the wall.
2. To use non linear p-y curve for modelling the passive resistance of soils due to lateral deformation of embedded wall section.
3. To analyse group affect on pile
Hope it helps.
This document summarizes a study analyzing the interaction between a jack-up rig's spudcans and an offshore pipeline during installation of the rig. Finite element modeling was used to evaluate soil deformation around the spudcan and at the pipeline. Both virgin soil profiles and modified profiles accounting for consolidation from a previous rig installation were considered. The results showed significant potential soil uplift near the pipeline. The modified soil profiles, with increased clay strength from consolidation, reduced predicted uplift. Overall, the study aimed to assess pipeline stability during the planned rig installation.
This document discusses soil mechanics and consolidation. It provides background on soil mechanics, explaining that it involves determining soil parameters and properties based on mechanical laws. It then focuses on consolidation, defining it as the process where saturated soil decreases in volume due to expulsion of pore water under pressure. The document outlines the theory of one-dimensional consolidation proposed by Terzaghi, describing how it can be used to determine rates of volume change, settlement, and pore pressure dissipation over time in saturated soils. It also discusses laboratory testing methods like oedometer tests that are used to characterize consolidation properties.
Consolidation settlement with sand drains – analytical and numerical approachesUmed Paliwal
The document discusses analytical and numerical approaches to studying consolidation settlement of foundations built on sand drains. The analytical part reviews existing literature on settlement, structure, installation and monitoring of sand drains. Popular theories on free strain and equal strain cases with and without smear are covered. The numerical part uses PLAXIS 2D to model a drain unit cell and address the reduction in consolidation time from sand drains under varying loads, the relationship between ultimate settlement and loading, and the relationship between ultimate settlement and drain diameter.
Fixity depth of offshore piles in elastoplastic soft clay under dynamic loadeSAT Journals
Abstract
This work represents study of dynamic behavior of offshore piles embedded in elastoplastic soft clay, and estimating the fixity depth of pile. ABAQUS finite element program which used to simulate the problem. The soil was modeled in two case elastic state model and elastoplastic state model represented by cam-clay model, three dimension element used to represent the interaction between pile and soil, and laboratory tests used to getting the real properties of clayey soil and to descried interface. The results obtained developed two empirical equations used to calculate depth of pile fixity for pile embedded in elastic and elastoplastic soil respectively. Also, show the depth of pile fixity is increase about (40 %) due to change soil model from elastic to plastic, when pile embedded in elastoplastic soil its dependent on soil strength, interface properties and pile rigidity. The pile head displacement is increase about 90 % while the bending moment is decease 10 % at pile head.
Fixity depth of offshore piles in elastoplastic soft clay under dynamic loadeSAT Journals
Abstract
This work represents study of dynamic behavior of offshore piles embedded in elastoplastic soft clay, and estimating the fixity depth of pile. ABAQUS finite element program which used to simulate the problem. The soil was modeled in two case elastic state model and elastoplastic state model represented by cam-clay model, three dimension element used to represent the interaction between pile and soil, and laboratory tests used to getting the real properties of clayey soil and to descried interface. The results obtained developed two empirical equations used to calculate depth of pile fixity for pile embedded in elastic and elastoplastic soil respectively. Also, show the depth of pile fixity is increase about (40 %) due to change soil model from elastic to plastic, when pile embedded in elastoplastic soil its dependent on soil strength, interface properties and pile rigidity. The pile head displacement is increase about 90 % while the bending moment is decease 10 % at pile head.
This document proposes methods for generating electricity from speed breakers. It discusses 5 classifications of speed breaker power generators that use different mechanisms: 1) a chain drive mechanism, 2) a rack and pinion system, 3) direct use of the load through a reciprocating device, 4) a translator and stator topology, and 5) a pressure lever mechanism. The document also outlines the advantages of using speed breakers for power generation such as low cost and maintenance and being a renewable source. Some challenges are also noted such as selecting a suitable generator and dealing with rain damage.
Cassava waste water was used as an admixture to replace distilled water in ratios of 5%, 10%, 15%, and 20% for producing sandcrete blocks. 60 sandcrete blocks of size 450mm x 150mm x 225mm were produced with different admixture ratios and a control with 0% admixture. The blocks were cured for 7, 14, 21, and 28 days and then tested for moisture content, specific gravity, water absorption, and compressive strength. Test results showed that blocks with 20% cassava waste water admixture met the minimum compressive strength requirement of 3.30 N/mm2 set by Nigerian standards, indicating the potential of cassava waste water to improve sandcrete block quality and
The document presents a theorem on random fixed points in metric spaces. It begins with introductions to fixed point theory, random fixed point theory, and relevant definitions. The main result is Theorem 3.1, which proves that if a self-mapping E on a complete metric space X satisfies certain contraction conditions involving parameters between 0 and 1, then E has a unique fixed point. The proof constructs a Cauchy sequence that converges to the unique fixed point. The document contributes to the study of random equations and random fixed point theory, which has applications in nonlinear analysis, probability theory, and other fields.
1. The document discusses applying multi-curve reconstruction technology to seismic inversion to improve accuracy and reliability. It focuses on reconstructing SP and RMN curves from well logs that are affected by various distortions.
2. The process of reconstructing the curves involves removing baseline drift, standardizing values, applying linear filtering, and fitting the curves. This removes interference and retains valid lithological information.
3. Reconstructing high quality curves improves the resolution and credibility of seismic inversion results. The method is shown to effectively predict sand distribution with little error.
This document compares the performance of a Minimum-Mean-Square-Error (MMSE) adaptive receiver and a conventional Rake receiver for receiving Ultra-Wideband (UWB) signals over a multipath fading channel. It first describes the UWB pulse shapes and channel model used, including the 6th derivative of the Gaussian pulse and the IEEE 802.15.3a modified Saleh-Valenzuela channel model. It then discusses the Direct-Sequence and Time-Hopping transmission and multiple access schemes for UWB. The document presents the receiver structures for the MMSE adaptive receiver and Rake receiver and compares their performance using MATLAB simulations.
This document summarizes a study on establishing logging interpretation models for reservoir parameters like porosity, permeability, oil saturation, and gas saturation in the Gaotaizi Reservoir of the L Oilfield. Models were developed using core data from 4 wells and include:
1) A porosity model relating acoustic travel time to porosity with an error of 0.92%
2) A permeability model relating permeability to porosity with an error of 0.31%
3) An oil saturation model using resistivity data with empirically determined parameters
4) A method to determine original gas saturation from mercury injection data.
Application of the models improved interpretation precision and allowed recalculation of oil and gas reserves for the
This document discusses predicting spam videos on social media platforms using machine learning. It proposes using attributes like number of likes, comments, and view count to classify videos as spam or not spam. A predictive algorithm is developed that uses threshold values for attributes and natural language processing of comments to classify videos. Testing of the algorithm on a dataset achieved a spam prediction precision of 93.6%. Issues with small datasets decreasing accuracy are also discussed, along with continuing work to address this issue.
1) The study experimentally evaluated the compatibility relationship between polymer solutions and oil layers through core flooding tests with different permeability cores.
2) The results showed that injection rate decreased with increasing polymer concentration and molecular weight, and increased with permeability.
3) Based on the results, boundaries for injection capability were established and a compatibility chart was proposed to guide polymer solution selection for different sedimentary microfacies in the field based on permeability and pore size.
1. The document discusses the identification of lithologic traps in the D3 Member of the Gaonan Region using seismic attribute analysis, acoustic impedance inversion, and sedimentary microfacies analysis.
2. Several lithologic traps were identified in the I and II oil groups of the D3 Member, with the largest trap located between wells G46 and G146X1 covering an area of about 2.35 km2.
3. Impedance inversion, seismic attribute analysis, and sedimentary microfacies characterization using 3D seismic data helped determine the location and development of effective lithologic traps in the thin sandstone-shale interbeds of the target stratum.
This document examines using coal ash as a partial replacement for cement in concrete. Coal ash was substituted for cement at rates of 5%, 10%, and 15% by weight. Testing found that concrete with a 5% substitution of coal ash exhibited only a slight decrease in compressive strength of 2% at 28 days while gaining improved workability. Higher substitution rates of 10% and 15% coal ash led to greater decreases in compressive and tensile strength. The study concludes that a 5% substitution of coal ash for cement provides benefits of reduced cost and improved workability with minimal strength impacts, representing an effective use of a waste material that addresses sustainability.
Accounting professional judgment involves handling accounting events and compiling financial reports according to regulations and standards. However, professional judgment is sometimes manipulated to distort accounting information. The document discusses three ways manipulation occurs: 1) abandoning accounting principles, 2) optional changes to accounting policies, and 3) abuse of accounting estimates. The causes of manipulation include distorted motivations from corporate governance issues and catering to various stakeholder interests. Strengthening supervision and improving the accounting system are proposed to manage manipulation of professional judgment.
The document discusses research on the distribution of oil and water in the eastern block of the Chao202-2 area in China. It establishes standards for identifying oil, poor oil, dry, and water layers using well logging data. Analysis shows structural reservoirs are dominant and fault and sand body configuration control oil-water distribution. Oil-water distribution varies between fault blocks from "up oil, bottom water" to "up water, bottom oil" depending on structure and sand body development.
The document describes an intelligent fault diagnosis system for reciprocating pumps that uses pressure and flow signals as inputs. It consists of hardware for data acquisition and a software system for signal processing, feature extraction, and fault diagnosis using wavelet neural networks. The system was able to accurately diagnose three main fault types - seal ring faults, valve damage, and spring faults - based on differences observed in the pressure curves. Testing on over 12 samples of each fault type achieved a correct diagnosis rate of over 94%. The system provides a fast and effective means of remotely monitoring reciprocating pumps and identifying faults.
This document discusses the application of meta-learning algorithms in banking sector data mining for fraud detection. It proposes using Classification and Regression Tree (CART), AdaBoost, LogitBoost, Bagging and Dagging algorithms for classification of banking transaction data. The experimental results show that Bagging algorithm has the best performance with the lowest misclassification rate, making it effective for banking fraud detection through data mining. Data mining can help banks detect patterns for applications like credit scoring, payment default prediction, fraud detection and risk management by analyzing customer transaction history and loan details.
This document presents a numerical solution for unsteady heat and mass transfer flow past an infinite vertical plate with variable thermal conductivity, taking into account Dufour number and heat source effects. The governing equations are non-linear and coupled, and were solved numerically using an implicit finite difference scheme. Various parameters, including Dufour number and heat source, were found to influence the velocity, temperature, and concentration profiles. Skin friction, Nusselt number, and Sherwood number were also calculated.
The document discusses methods for obtaining a background image using depth information from a depth camera to more accurately extract foreground objects. It finds that accumulating depth images and taking the median value at each pixel provides the most accurate background image. The accuracy of three methods - average, median, and mode - are evaluated using simulated depth data of a captured plane. The median method provides the best results, followed by average, while mode performs worst. More accumulated images provide a more accurate background image across all methods.
This document presents a mathematical model for determining the minimum overtaking sight distance (OSDm) required for an ascending vehicle to safely pass another slower vehicle on a single lane highway with an incline. It defines sight distance, stopping sight distance, perception-reaction time and derives equations to calculate the reaction distance (d1), overtaking distance (d2), vehicle travel distance during overtaking (d3), and total minimum OSDm based on vehicle characteristics, road geometry, and coefficients of friction. The safe overtaking zone is defined as 3 times the minimum OSDm. The model accounts for effects of slope angle and aims to satisfy laws of mechanics for overtaking maneuvers on inclined two-way single lane highways.
This document discusses a novel technique for better analysis of ice properties using Kalman filtering. It summarizes previous research on sea ice segmentation using SAR imagery and dual polarization techniques. It proposes using an automated SAR algorithm along with Kalman filtering to more accurately detect sea ice properties from RADARSAT1 and RADARSAT2 imagery data. The document reviews techniques for image segmentation, dual polarization, PMA detection, and related work on sea ice classification using statistical ice properties, edge preserving region models, and object extraction methods.
This document summarizes a study on the bioaccumulation of heavy metals in bass fish (Morone Saxatilis) caught at Rodoni Cape in the Adriatic Sea in Albania. Samples of bass fish were collected from five sites and analyzed for mercury, lead, and cadmium levels in their muscles. The concentrations of heavy metals varied between fish and sites but were below international limits for human consumption. While the fish were found to be safe for eating, the study recommends continuous monitoring of metal levels in fish from the area due to various factors that can influence metal uptake over time.
This document discusses optimal maintenance policies for repairable systems with linearly increasing hazard rates. It considers a system with a constant repair rate and predetermined availability requirement. There are two maintenance policies: corrective maintenance only, and preventive maintenance at set time intervals. The goal is to determine the preventive maintenance interval that guarantees the availability requirement at minimum cost. Equations are developed to calculate the availability under each policy and the optimal preventive maintenance interval based on both availability and cost. A numerical example is provided to demonstrate the decision process in determining the optimal policy.
Pushing the limits of ePRTC: 100ns holdover for 100 daysAdtran
At WSTS 2024, Alon Stern explored the topic of parametric holdover and explained how recent research findings can be implemented in real-world PNT networks to achieve 100 nanoseconds of accuracy for up to 100 days.
Unlocking Productivity: Leveraging the Potential of Copilot in Microsoft 365, a presentation by Christoforos Vlachos, Senior Solutions Manager – Modern Workplace, Uni Systems
Removing Uninteresting Bytes in Software FuzzingAftab Hussain
Imagine a world where software fuzzing, the process of mutating bytes in test seeds to uncover hidden and erroneous program behaviors, becomes faster and more effective. A lot depends on the initial seeds, which can significantly dictate the trajectory of a fuzzing campaign, particularly in terms of how long it takes to uncover interesting behaviour in your code. We introduce DIAR, a technique designed to speedup fuzzing campaigns by pinpointing and eliminating those uninteresting bytes in the seeds. Picture this: instead of wasting valuable resources on meaningless mutations in large, bloated seeds, DIAR removes the unnecessary bytes, streamlining the entire process.
In this work, we equipped AFL, a popular fuzzer, with DIAR and examined two critical Linux libraries -- Libxml's xmllint, a tool for parsing xml documents, and Binutil's readelf, an essential debugging and security analysis command-line tool used to display detailed information about ELF (Executable and Linkable Format). Our preliminary results show that AFL+DIAR does not only discover new paths more quickly but also achieves higher coverage overall. This work thus showcases how starting with lean and optimized seeds can lead to faster, more comprehensive fuzzing campaigns -- and DIAR helps you find such seeds.
- These are slides of the talk given at IEEE International Conference on Software Testing Verification and Validation Workshop, ICSTW 2022.
GraphRAG for Life Science to increase LLM accuracyTomaz Bratanic
GraphRAG for life science domain, where you retriever information from biomedical knowledge graphs using LLMs to increase the accuracy and performance of generated answers
How to Get CNIC Information System with Paksim Ga.pptxdanishmna97
Pakdata Cf is a groundbreaking system designed to streamline and facilitate access to CNIC information. This innovative platform leverages advanced technology to provide users with efficient and secure access to their CNIC details.
Climate Impact of Software Testing at Nordic Testing DaysKari Kakkonen
My slides at Nordic Testing Days 6.6.2024
Climate impact / sustainability of software testing discussed on the talk. ICT and testing must carry their part of global responsibility to help with the climat warming. We can minimize the carbon footprint but we can also have a carbon handprint, a positive impact on the climate. Quality characteristics can be added with sustainability, and then measured continuously. Test environments can be used less, and in smaller scale and on demand. Test techniques can be used in optimizing or minimizing number of tests. Test automation can be used to speed up testing.
GraphSummit Singapore | The Future of Agility: Supercharging Digital Transfor...Neo4j
Leonard Jayamohan, Partner & Generative AI Lead, Deloitte
This keynote will reveal how Deloitte leverages Neo4j’s graph power for groundbreaking digital twin solutions, achieving a staggering 100x performance boost. Discover the essential role knowledge graphs play in successful generative AI implementations. Plus, get an exclusive look at an innovative Neo4j + Generative AI solution Deloitte is developing in-house.
UiPath Test Automation using UiPath Test Suite series, part 5DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 5. In this session, we will cover CI/CD with devops.
Topics covered:
CI/CD with in UiPath
End-to-end overview of CI/CD pipeline with Azure devops
Speaker:
Lyndsey Byblow, Test Suite Sales Engineer @ UiPath, Inc.
GraphSummit Singapore | The Art of the Possible with Graph - Q2 2024Neo4j
Neha Bajwa, Vice President of Product Marketing, Neo4j
Join us as we explore breakthrough innovations enabled by interconnected data and AI. Discover firsthand how organizations use relationships in data to uncover contextual insights and solve our most pressing challenges – from optimizing supply chains, detecting fraud, and improving customer experiences to accelerating drug discoveries.
Communications Mining Series - Zero to Hero - Session 1DianaGray10
This session provides introduction to UiPath Communication Mining, importance and platform overview. You will acquire a good understand of the phases in Communication Mining as we go over the platform with you. Topics covered:
• Communication Mining Overview
• Why is it important?
• How can it help today’s business and the benefits
• Phases in Communication Mining
• Demo on Platform overview
• Q/A
TrustArc Webinar - 2024 Global Privacy SurveyTrustArc
How does your privacy program stack up against your peers? What challenges are privacy teams tackling and prioritizing in 2024?
In the fifth annual Global Privacy Benchmarks Survey, we asked over 1,800 global privacy professionals and business executives to share their perspectives on the current state of privacy inside and outside of their organizations. This year’s report focused on emerging areas of importance for privacy and compliance professionals, including considerations and implications of Artificial Intelligence (AI) technologies, building brand trust, and different approaches for achieving higher privacy competence scores.
See how organizational priorities and strategic approaches to data security and privacy are evolving around the globe.
This webinar will review:
- The top 10 privacy insights from the fifth annual Global Privacy Benchmarks Survey
- The top challenges for privacy leaders, practitioners, and organizations in 2024
- Key themes to consider in developing and maintaining your privacy program
UiPath Test Automation using UiPath Test Suite series, part 6DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 6. In this session, we will cover Test Automation with generative AI and Open AI.
UiPath Test Automation with generative AI and Open AI webinar offers an in-depth exploration of leveraging cutting-edge technologies for test automation within the UiPath platform. Attendees will delve into the integration of generative AI, a test automation solution, with Open AI advanced natural language processing capabilities.
Throughout the session, participants will discover how this synergy empowers testers to automate repetitive tasks, enhance testing accuracy, and expedite the software testing life cycle. Topics covered include the seamless integration process, practical use cases, and the benefits of harnessing AI-driven automation for UiPath testing initiatives. By attending this webinar, testers, and automation professionals can gain valuable insights into harnessing the power of AI to optimize their test automation workflows within the UiPath ecosystem, ultimately driving efficiency and quality in software development processes.
What will you get from this session?
1. Insights into integrating generative AI.
2. Understanding how this integration enhances test automation within the UiPath platform
3. Practical demonstrations
4. Exploration of real-world use cases illustrating the benefits of AI-driven test automation for UiPath
Topics covered:
What is generative AI
Test Automation with generative AI and Open AI.
UiPath integration with generative AI
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Unlock the Future of Search with MongoDB Atlas_ Vector Search Unleashed.pdfMalak Abu Hammad
Discover how MongoDB Atlas and vector search technology can revolutionize your application's search capabilities. This comprehensive presentation covers:
* What is Vector Search?
* Importance and benefits of vector search
* Practical use cases across various industries
* Step-by-step implementation guide
* Live demos with code snippets
* Enhancing LLM capabilities with vector search
* Best practices and optimization strategies
Perfect for developers, AI enthusiasts, and tech leaders. Learn how to leverage MongoDB Atlas to deliver highly relevant, context-aware search results, transforming your data retrieval process. Stay ahead in tech innovation and maximize the potential of your applications.
#MongoDB #VectorSearch #AI #SemanticSearch #TechInnovation #DataScience #LLM #MachineLearning #SearchTechnology
Full-RAG: A modern architecture for hyper-personalizationZilliz
Mike Del Balso, CEO & Co-Founder at Tecton, presents "Full RAG," a novel approach to AI recommendation systems, aiming to push beyond the limitations of traditional models through a deep integration of contextual insights and real-time data, leveraging the Retrieval-Augmented Generation architecture. This talk will outline Full RAG's potential to significantly enhance personalization, address engineering challenges such as data management and model training, and introduce data enrichment with reranking as a key solution. Attendees will gain crucial insights into the importance of hyperpersonalization in AI, the capabilities of Full RAG for advanced personalization, and strategies for managing complex data integrations for deploying cutting-edge AI solutions.
For the full video of this presentation, please visit: https://www.edge-ai-vision.com/2024/06/building-and-scaling-ai-applications-with-the-nx-ai-manager-a-presentation-from-network-optix/
Robin van Emden, Senior Director of Data Science at Network Optix, presents the “Building and Scaling AI Applications with the Nx AI Manager,” tutorial at the May 2024 Embedded Vision Summit.
In this presentation, van Emden covers the basics of scaling edge AI solutions using the Nx tool kit. He emphasizes the process of developing AI models and deploying them globally. He also showcases the conversion of AI models and the creation of effective edge AI pipelines, with a focus on pre-processing, model conversion, selecting the appropriate inference engine for the target hardware and post-processing.
van Emden shows how Nx can simplify the developer’s life and facilitate a rapid transition from concept to production-ready applications.He provides valuable insights into developing scalable and efficient edge AI solutions, with a strong focus on practical implementation.
“Building and Scaling AI Applications with the Nx AI Manager,” a Presentation...
F04653441
1. IOSR Journal of Engineering (IOSRJEN) www.iosrjen.org
ISSN (e): 2250-3021, ISSN (p): 2278-8719
Vol. 04, Issue 06 (June. 2014), ||V5|| PP 34-41
International organization of Scientific Research 34 | P a g e
Stress Distribution in Soils under Pile Cap of Tapered Piles in
Compressible Clay
T.W. Adejumo1
1
Department of Geotechnics and Environmental Engineering, Faculty of Civil Engineering, Belarusian National
Technical University, Minsk, Belarus.
Abstract: - This research paper presents the results of comprehensive investigations on stress distribution in soils
under pile cap of tapered piles in compressible clay. Compressible clay from Urucha and Shabani, area of Minsk
province, Belarus was investigated in this work. The former was used for laboratory investigation, while field
tests were conducted on the latter respectively. The results show the influence of axial compressive load on the
magnitude, pattern and orientation of stresses in soils under the pile cap of loaded modeled instrumental piles
bored into compressive clay soil. Stresses in the soils at different depths under the pile cap with reference to pile
center lines were measured and compared with those obtained using Boussinesq’s theory. Measured stresses are
slightly higher than those calculated using the theory. The investigations also showed that, for tapered piles
bored in compressive clay, the stress increases towards the center line of pile-pile cap joint irrespective of
tapering angle only up to 0.5m below the cap, (model), beyond this point, the magnitude and pattern of stress
changes. The vertical normal stress under the pile cap increases from zero at the surface to 42% in depth lower
than 3.5R, and 55% beyond this point. The maximum principal stress is directed along the radius vector R and
reduces radially outward from the pile centerline. The normal and shear stress vectors are less in pile with higher
center to center spacing. In addition, stress distribution under pile cap is also a function of pile spacing and
tapering angle. Clearly striated stressed zones of deformation under loaded pile cap, having depth in multiples of
pile diameter were observed.
Keywords: - Compressible clay, Deformation, Settlement, Stress in soil, Tapered pile
I. INTRODUCTION
As foundation engineers, a significant amount of the work we do is based on the concept of stress.
Stress analysis allows us to obtain the normal and shear stresses in any plane passing through a point, given the
normal and shear stresses acting on mutually perpendicular planes passing through the point [1]. When pile is
penetrates in a downward frictional mode, a failure zone is developed along the soil-pile interface which partly
upheaves laterally and disturbs the soil below the pile tip. Partly consolidation develops around soil-pile
interface when soil compresses elastically below the critical depth [2].
The pile cap is defined as a structural member used to distribute the load to the piles [3]. The flexibility
of the pile cap affects individual pile head forces significantly and affects the bending moments and shear forces
in individual piles as well, even though the displacement of the pile cap does not vary much [4]. When the pile
cap distributes an equal magnitude of load on each pile, the following assumption must be satisfied according to
Bowles; (a) the pile cap is in contact with the ground, (b) the piles are all vertical, (c) a load is applied at center
of pile group, and (d) the pile group is symmetrical [3].
Investigations and data on measured stress in clay are limited, and even the available few are mostly for
compacted clays. There is almost no convenient way of inserting a load cell into natural (undisturbed) clay
without causing severe stress redistribution problems. A variety of laboratory tests as well as field techniques
are available, each having its own limitations as well as advantages [5]. Equations for the stresses and strains
induced in a homogeneous, isotropic, weightless, linearly elastic half space, with a plane horizontal surface, by a
point load perpendicular to the surface and acting at the surface, was first solved in usable form by Boussinesq
[6] & [7], and later by Acum and Fox [8], with a few others in between. Foster and Fergus obtained information
on the spatial variation in developed pressure in compacted clay. They concluded that Boussinesq's theory is
adequately accurate, at least for compacted clays [9]. Solutions for the stress and deformation caused by a
vertical point load applied at the surface have been presented by Koning [10] and Barber [11]. Biot established
an equation for determination of normal stress in rigid floor [12]. Cummings worked further on Biot’s equations
to determine the vertical normal stress on the base directly beneath the center of a uniformly loaded disc [13].
The lateral deformation of piles decreases with increase in distance from the pile center line, while outward
radial deformations recorded around the pile decreases downwards along the length [14]. The skin friction and
radial stress are highly influenced by tapered piles compared with conventional piles. The tapering and wedging
2. Stress Distribution in Soils under Pile Cap of Tapered Piles in Compressible Clay
International organization of Scientific Research 35 | P a g e
effects are responsible for increase in normalized skin friction and normalized lateral stresses. Taper-shaped
piles offer a larger resistance than the cylindrical piles [2] and [15].
Although the assumptions are usually made that the soil is homogeneous and isotropic, it is apparent
that most field problems involve soils that are stratified and anisotropic [16]. Based on the strength of their
digenetic bonds, clay and clay-shale have been grouped into 3: 1) over consolidated plastic clay with weak or no
bond; 2) over consolidated plastic clay with well-developed digenetic bonds and c) over consolidated plastic
clay with strongly-developed digenetic bonds [17]. Clay soils around Minsk region falls into the third category
[18]-[20]. In spite of these results however, more work still needed to be done for greater understanding of the
dynamics of pile-soil or pile cap-soil behavior under stress.
The object of this paper therefore, is to present the results of a series of modeled pile tests on stress
distribution under the pile cap of tapered piles conducted in the research laboratory, Geotechnical and
Environmental Engineering department, Belarusian National Technical University, Minsk, and field tests on the
outskirt of Minsk province, Belarus. This investigation is essential in the understanding of structural behavior of
the soil under axially loaded pile cap of tapered piles, and its response to loading. Obtaining the stress
distribution of soil immediately the below the piles cap under loads is a key factor to understanding its behavior
and response to deformation and utmost functionality. The foregoing therefore, explains the relevance of this
investigation.
II. MATERIALS AND METHOD
The materials and method employed in this work can simply be divided into; a) theoretical
determination of the stress exerted on the soil using Boussinesq equation, b) laboratory investigations for the
model tapered piles, c) field tests with bored tapered piles having pile cap in contact with the soil, and d)
analysis of both calculated and measured stress from the controlled tests.
1.1 Theoretical Determination of Stress
Besides the tabulation of Ahlvin and Uleri [21], increase in vertical stress at any point below a
rectangular area subjected to uniform load can be calculated using Boussinesq’s solution [22], [16]. For most
practical analyses of the settlement behavior of soils, it is assumed that the volume of the soil is controlled
exclusively by the vertical stress, σz. Using Boussinesq solution and r-t-z coordinate system, superimposed on
the traditional x-y coordinates, the vertical stress in soil under the axially loaded pile cap in Fig. 1 is given by:
Where P is axial load; I is influence factor (ratio of r/z) given by Terzaghi [23] and Taylor [24];
P
r
z
r
R z
t
Pile cap
Fig. 1: Symbols and direction of entities used in the equation for stress under axially loaded pile cap
Introducing x-axis in disperses and Poisson’s ratio, the spatial distribution of normal stress and
shearing stress is given by the equations:
3. Stress Distribution in Soils under Pile Cap of Tapered Piles in Compressible Clay
International organization of Scientific Research 36 | P a g e
1.2 Laboratory Investigations
Clay samples tested were taken from a construction site at Urucha, at the outskirt of Minsk, Belarus.
The soil was conditioned and detailed laboratory investigation was carried out to determine the stress
distribution under the pile cap when modeled tapered piles were bored into it. The test with modeled piles of
20mm diameter and 200mm long was conducted in the test tank shown in Fig. 2, in the post graduate laboratory
of the Department of Geotechnics & Civil Engineering, Faculty of Civil Engineering, Belarusian National
University, Minsk, Belarus. A detailed, easy-to-follow procedure on this has been covered in my earlier works;
Adejumo et al [25] and Adejumo [26]. Test results were collected and collated for further analysis.
1.3 Field Investigations
The field tests were performed on 4 No 320mm diameter tapered piles with tapering angles (α) of 1.43o
and 0.950, and group efficiency of 0.85 and 0.95 at two test points respectively, at a construction site in Shabani
industrial layout, on the outskirt of Minsk. The pile cap configuration is 2260 X 2260 X 500mm in dimension.
Static loads were applied and maintained using a hydraulic jack (of 200T capacity) and were measured with a
load cell as shown in Fig. 3. Reaction to the jack load is provided by a steel frame that is attached to an array of
steel H-piles located at least 1.5m away from the test piles. Pile cap settlements were measured relative to a
fixed reference beam using 2 dial gauges. Displacement/settlement of soils around the piles measurements were
made in reference to the pile cap using 5 dial gauges, Fig. 4. The settlements were recorded for each loading
increment at an interval of 15 minutes or the time when the movement of the indicator on the dial gauges
becomes insignificant. The modeled test piles were instrumented with strain gauges connected to the stylishly
perforated steel cone-heads by string-pulley (for static resistance) with censors to the pile centerline. The steel
cone-heads with series of springs connected to the indicators were installed in the soils around the piles at
depths 0.2m, 0.5m, 1.0m 1.5m, and the 5th one at 0.2m outside the pile cap. The piles were subjected to axial
compressive loads until the allowable pile settlement of 0.1d (10% of pile diameter) is reached or exceeded in
line with the submission of [27-29]. The vertical normal stress and deformation during loading and unloading
were then recorded.
4. Stress Distribution in Soils under Pile Cap of Tapered Piles in Compressible Clay
International organization of Scientific Research 37 | P a g e
Fig. 2: Testing tank for laboratory investigations
Fig. 3: Loading device for field investigations (200Tonnes capacity)
Fig. 4: Dial guages for sensor movement measurement under pile cap
5. Stress Distribution in Soils under Pile Cap of Tapered Piles in Compressible Clay
International organization of Scientific Research 38 | P a g e
III. RESULTS AND DISCUSSION
The results of geotechnical properties of the compressive clay investigated in the laboratory is
presented in Table1 below. It shows a high void ration (e) and cohesion with maximum values of 1.92 and 30
kPa respectively, which indicated the compressibility of the sample. It does not drain readily and may absorb
water by capillary action, which lead to loss of strength.
Table 1: Summary of geotechnical properties of tested clay sample
Parameters Values for the Sample
Highvoidratio(e)andcohesion
indicatethecompressibilityofthe
claysample
Density γ (kN/m3
) 18
Moisture content (w) 10
Specific gravity of solids 2.63
Liquid Limit (%) 23 - 29
Plastic Limit (%) 17 - 19
Plasticity index (%) 5 - 10
Liquidity Index (%) 0.1 – 0.3
Void ratio (e) 0.70 - 1.92
Cohesion (kPa) 25 - 30
Angle of internal friction (φo
) 7 - 18
Modulus of Deformation E
(kPa)
7.5 - 13
The result of theoretical (calculated) stress is shown in Table 2. Using the r-t-z coordinate system, with
the normal stress equal to the radius vector R at equilibrium, the maximum vertical shear stress beyond which
the soil experiences yield is 7.03 kPa. Table 3 shows the normal and shear stress measured during loading and
unloading. It shows slightly higher shear stress value of 7.39 kPa for the corresponding load. The vector
correlation coefficient of r = 0.922 was obtained for the calculated and the experimental stress.
Table 2: Calculated (Theoretical) vertical normal and shear stress under pile cap
Load
(MPa) 0.00 0.50 1.00 1.50 2.00 2.50 3.00
Stress
(kPa)
σ τ σ τ σ τ σ τ σ τ σ τ σ τ
Pile
cap 0.00 0.00 0.09 6.47 0.19 6.55 0.29 6.67 0.37 6.67 0.49 6.78 0.59 6.86
0.2m 0.00 0.00 0.09 6.45 0.19 6.56 0.29 6.66 0.38 6.68 0.50 6.88 0.60 6.89
0.5m 0.00 0.00 0.09 6.47 0.20 6.58 0.29 6.67 0.36 6.67 0.49 6.88 0.59 6.86
1.0m 0.00 0.00 0.10 6.48 0.21 6.59 0.30 6.68 0.39 6.77 0.51 6.89 0.62 6.99
1.5m 0.00 0.00 0.11 6.49 0.22 6.60 0.34 6.72 0.41 6.79 0.54 6.92 0.65 7.03
Table 3: Measured (Field) vertical normal and shear stress under pile cap
Load
(MPa) 0.00 0.50 1.00 1.50 2.00 2.50 3.00
Stress
(kPa)
σ τ σ τ σ τ σ τ σ τ σ τ σ τ
Pile
cap 0.00 0.00 0.10 6.85 0.19 6.93 0.29 7.03 0.37 7.11 0.49 7.23 0.59 7.33
0.2m 0.00 0.00 0.09 6.83 0.19 6.93 0.29 7.03 0.38 7.12 0.50 7.24 0.60 7.34
0.5m 0.00 0.00 0.10 6.85 0.20 6.94 0.29 7.03 0.36 7.10 0.49 7.23 0.59 7.33
1.0m 0.00 0.00 0.10 6.84 0.21 6.95 0.30 7.04 0.39 7.13 0.51 7.25 0.62 7.39
1.5m 0.00 0.00 0.11 6.86 0.22 6.97 0.34 7.08 0.41 7.15 0.54 7.28 0.65 7.39
The Load-settlement curves for the laboratory instrumented tapered piles are shown in Figs. 5 and 6.
Soils around tapered piles with higher tapering angle (α) show less settlement (5-10% lower) at the initial period
of loading. However, they produced a generally higher settlement and deformations in soils closer to and around
the pile tip with a depth of failure tip influence zone 10 times the pile diameter, while those with less tapering
6. Stress Distribution in Soils under Pile Cap of Tapered Piles in Compressible Clay
International organization of Scientific Research 39 | P a g e
angle is 7.5 times their diameter. Pile cap settlement is 110% and 102% higher than soil settlements around
tapered piles with tapering angles of 0.950
and 1.430
respectively.
Fig. 5: Settlement of soils withα of 0.95o
Fig. 6: Settlement of soils withα of 1.43o
Vertical and spatial stress along the pile axis under pile cap follow the usual pattern as shown in the
failure bulb around an idealized pile of the four in a group of 4-piles in Fig. 7. It also followed the pattern of
increasing radially outward from pile center in agreement with the finding of Salgado [30]. Four zones of
deformation with depth of 2.5D, 3D, 2.5D, and 2D from pile cap line downward. D is diameter of pile.
7. Stress Distribution in Soils under Pile Cap of Tapered Piles in Compressible Clay
International organization of Scientific Research 40 | P a g e
P
75
100
125
150
175
200
300
275
250
Zone 4
0.0
25
50
225
Zone 3
4 Zones of deformation
Zone 2
Zone 1
Stress/vectors
Fig. 7: Spatial movement and settlement of soils under axially loaded pile cap
IV. CONCLUSION
The stress distribution pattern, intensity and magnitude in soil around tapered piles bored into
compressive clay soil obtained from sites on the outskirt of Minsk region, when subjected to compressive axial
loads investigated in this study have been presented. The results of the investigations showed that in
compressive clay, the stress increases towards the center line of pile-pile cap joint of tapered piles irrespective
of tapering angle only up to 0.5m below the cap, (same as depth of pile cap itself), beyond this point, the
magnitude and pattern of stress changes. The vertical normal stress under the pile cap increases from zero at the
surface to 42% in depth lower than 3.5R, and 55% beyond this point. The maximum principal stress is directed
along the radius vector R and reduces radially outward from the pile centerline. The shear stress value beyond
the radius vector, R is of 7.03 kPa for the calculated/theoretical test, while a higher value 7.39 kPa was obtained
on the field. The average depth of failure zone for tapered piles with pile spacing (η) of 0.95, and tapering angle
(α) 0.950
is 7.5 times pile diameter, whereas it’s 10 times diameter of piles when the tapering angle is increased
to 1.430
. Stress intensity, which is directly proportional to settlement, is also influenced by the tapering angle
relative to the diameter of the pile, and this effect increases with incremental depth of pile penetration into
compressive clay soil. Pile cap settlement is 5-10% higher in tapered piles with lower tapering angle. While
laboratory test revealed soils on the upper layer of tapered piles with higher tapering angle underwent greater
stress, the field tests result shows the contrary. Slightly larger confining pressure for the laboratory test as well
as induced stress on the field may be responsible for this.
V. ACKNOWLEDGEMENTS
The author is grateful I.L. Boiko and M. Alhassan for their contributions, JSC Syncline and
GEOSERVICE Minsk, for the machinery and detailing, as well as other technical staff who assisted during the
investigations.
REFERENCES
[1] R. Hooke and J. B. Hansen, Stress analysis, Strain analysis and Shearing of soils, in The Engineering of
foundations, available at http://.mcgraw-hill.com/sites/dl/free/0072500581/373512/Ch04.pdf
[2] S. Manandhar and N. Yasufuku, Evaluation of skin friction of tapered piles in sands based on Cavity
Expansion Theory, Memoirs of the Faculty of Engineering, Kyushu University, Vol. 71(4), 2011, 101-
126.
[3] J. E. Bowles, Foundation analysis and design 5th Edition, (Singapore: McGraw-Hill, 1997).
[4] J. Won, S.Y. Ahn, S. Jeong, J. Lee and S.Y. Jang, Nonlinear three-dimensional analysis of pile group
supported columns considering pile cap flexibility, Computers and Geotechnics, (33), 2006, 355-370.
[5] B. M. Das and G. V. Ramana, Principles of soil dynamics 2nd
Edition, (Stamford CT Connecticut:
Cenpage Learning, 2011).
[6] M. V. Boussinesq, Application des Potentiels â L’Etude de L’Équilibre et du Mouvement des Solides
Élastiques, Gauthier-Villars, Paris, 1885.
8. Stress Distribution in Soils under Pile Cap of Tapered Piles in Compressible Clay
International organization of Scientific Research 41 | P a g e
[7] M. J. Boussinesq, Application des potentiels a l'etude de l'equilibre et du movement des solides
elastiques, principalement au calcul des deformations et des pressions que produisent, dans ces solides,
des efforts quelconques exerces sur une petite partie de leur surface ou de leur interieur: Memoire suivi de
notes etendues sur divers points de physique mathematique et d'analyse," GauthierVillars, Paris, 1885,
pp. 722.
[8] W. E. A. Acum and L. Fox, Computation of Load Stresses in a Three Layer Elastic System,
Geotechnique, Vol. 2, 1951, 293-300.
[9] C. R Foster and S. M. Fergus, Stress Distribution in a Homogeneous Soil, Res. Report No. 12-F, Highway
Research Board, 1951, 36 pp.
[10] H. Koning, Stress Distribution in a Homogeneous, Anisotropic, Elastic Semi-Infinite Solid, Proc., Fourth
Intern. Conf. on Soil Mech. and Found. Engr., Vol. II, 1957, 335-338.
[11] E. S. Barber, Shear Loads on Pavements, Proceedings, International Conference on the Structural Design
of Asphalt Pavements, Univ. of Michigan, 1963.
[12] M.A. Biot, Effect of Certain Discontinuities on the Pressure Distribution in a Loaded Soil, Physics, Vol.
6, 1935, 367-375.
[13] A. E. Cummings, Distribution of Stresses Under a Foundation, Transactions, ASCE, Vol. 101, 1936,
1072-1134
[14] T. W. Adejumo, Settlement and Deformation Pattern of Modeled Wooden Piles in Clay, International
Journal of Advanced Technology and Engineering Research, Vol.3 (3), 2013, 94-99.
[15] S. Manandhar, N. Yasufuku and K. Omine, Application of cavity expansion theory for evaluation of skin
friction of tapered piles in sands, International Journal of Geo-Engineering, 4(3), 2012, 5-17.
[16] R. E. Olson, Advance Soil Mechanics: Stress Distribution, Unit 8, available at
http://www.cyut.edu.tw/~jrlai/CE7332/Chap8.pdf
[17] L. Bjerrum, Progressive failure in Slopes of Over-consolidated Plastic Clays and Clay-shales, Proc.
ASCE, 93(SM 5), 1967, 3–49.
[18] M. Alhassan, T. W. Adejumo and I. L. Boiko, Classification of Subsoil Bases in Nigeria. Electronic
Journal of Geotechnical Engineering, 17 (J), 2012, 1407-1413.
[19] ГОСТ20276-99 Грунты. Методы полевого определения характеристик прочности и дефор-
мируемости: ГОСТ20276-99. – Введ. 13.07.2000. – Минск: Межгос. науч.-технич. комиссия по
стандартизации, технич. нормированию и сертифика-ции в строительстве: НИИОСП им.
Герсеванова, 2001. – 56 с.
[20] Г. К. Клейн, Расчет низких ростверков с учетом совместности их работы со сваями и основанием/
Г.К. Клейн, С.И. Родин// Научно-технический жур-нал. Основания, фундаменты и механика
грунтов. – №4. 1977, С. 16–17.
[21] R. E. Ahlvin and H. H. Ulery, Tabulated Values for Determining the Complete Pattern of Stresses,
Strains, and Deflections Beneath a Uniform Circular Load on a Homogeneous Half Space, Stress
Distribution in Earth Masses, Highway Research Bulletin No. 342, 1962, 1-13.
[22] B. M. Das, Principles of geotechnical engineering 6th
Edition, (Canada: Thomson, 2006).
[23] K. Terzaghi, Theoretical Soil Mechanics, John Wiley and Sons, New York City, 1943, pp. 510.
[24] D. W. Taylor, Fundamentals of Soil Mechanics, John Wiley and Sons, New York, 1948, City, pp. 700.
[25] T. W ADEJUMO, M. ALHASSAN and I. L. BOIKO, Laboratory Investigation of Load Incremental
Effect on the Deformation of Clay under Axially loaded Modeled Circular Piles, 11th International
Conference “Modern Building Materials, Structures and Techniques”, Vilnius Gediminas Technical
University, Vilnius, Lithuania, Procedia Engineering, Elsevier Journals, Vol. 57, 2013, 83-87.
[26] T. W. ADEJUMO, Settlement Analysis of Wooden Piles in Clay, International Journal of Science,
Engineering and Technology Research, Vol. 2(4), 2013, 778-782.
[27] H. G. Poulos, J. P. Carter and J. C. Small, Foundations and Retaining Structures–Research and Practice;
State of the Art Lecture, Proc. 15th Int. Conf. Soil Mechs, Found. Eng., Istanbul, (4), 2002, 2527-2606.
[28] N. K. S. Al–Saoudi and H. M. Salim, The Behavior of groups of reinforced concrete model piles in
expansive soil, Proc. of the 2nd International Conference on Unsaturated Soils, Beijing, Vol.1, 1998,
321-326.
[29] M. J. Tomlinson, Foundation design and construction 5th edition, (Upper Saddle River, NJ: Prentice
Hall, 2001).
[30] R.Salgado, The engineering of foundations 1st
Edition, (New York: McGraw-Hill, 2008).