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.
Class notes of Geotechnical Engineering course I used to teach at UET Lahore. Feel free to download the slide show.
Anyone looking to modify these files and use them for their own teaching purposes can contact me directly to get hold of editable version.
This ppt is more useful for Civil Engineering students.
I have prepared this ppt during my college days as a part of semester evaluation . Hope this will help to current civil students for their ppt presentations and in many more activities as a part of their semester assessments.
I have prepared this ppt as per the syllabus concerned in the particular topic of the subject, so one can directly use it just by editing their names.
Regarding Types of Foundation, Methods, Uses of different types of foundation at different soil properties. Methods of construction of different types of foundation, Codal Provisions etc.
The document provides information about slope stability analysis. It defines a slope and describes natural and man-made slopes. It discusses causes of slope failure such as gravitational forces, seepage, erosion, and earthquakes. Methods of slope stability analysis are described including infinite slope analysis, finite slope analysis using wedge failure, friction circle, and Swedish circle methods. Factors of safety are defined with respect to shear strength, cohesion, and friction. The aims of slope stability analysis are to assess stability, understand failure mechanisms, and design preventive measures.
DESTRUCTIVE AND NON-DESTRUCTIVE TEST OF CONCRETEKaran Patel
The standard method of evaluating the quality of concrete in buildings or structures is to test specimens cast simultaneously for compressive, flexural and tensile strengths.
The main disadvantages are that results are not obtained immediately; that concrete in specimens may differ from that in the actual structure as a result of different curing and compaction conditions; and that strength properties of a concrete specimen depend on its size and shape.
Although there can be no direct measurement of the strength properties of structural concrete for the simple reason that strength determination involves destructive stresses, several non- destructive methods of assessment have been developed.
Consolidation is the process where water drains from saturated soil pores, transferring the load from water to soil particles and causing volume change. There are three types of consolidation: immediate, primary, and secondary. One-dimensional consolidation assumes vertical drainage, making the process primarily vertical. Terzaghi's theory of one-dimensional consolidation models this using parameters like permeability, compressibility, and effective stress. The coefficient of consolidation describes the rate of compression, while compression and swelling indices characterize the void ratio-effective stress relationship. The oedometer test experimentally determines consolidation properties from soil specimen compression under incremental loads.
This document provides an overview of slope stability and analysis. It defines different types of slopes as natural, man-made, infinite and finite. Common causes of slope failure like erosion, seepage, drawdown, rainfall, earthquakes and external loading are described. Key terms used in slope stability are defined, including slip zone, slip plane, sliding mass and slope angle. Types of slope failures are identified as face/slope failure, toe failure and base failure. Methods for analyzing finite slope stability, like Swedish circle method, Bishop's simplified method and Taylor's stability number are introduced. Infinite slope analysis is described for cohesionless, cohesive and cohesive-frictional soils. Example tutorial problems on slope stability calculations are
Class notes of Geotechnical Engineering course I used to teach at UET Lahore. Feel free to download the slide show.
Anyone looking to modify these files and use them for their own teaching purposes can contact me directly to get hold of editable version.
This ppt is more useful for Civil Engineering students.
I have prepared this ppt during my college days as a part of semester evaluation . Hope this will help to current civil students for their ppt presentations and in many more activities as a part of their semester assessments.
I have prepared this ppt as per the syllabus concerned in the particular topic of the subject, so one can directly use it just by editing their names.
Regarding Types of Foundation, Methods, Uses of different types of foundation at different soil properties. Methods of construction of different types of foundation, Codal Provisions etc.
The document provides information about slope stability analysis. It defines a slope and describes natural and man-made slopes. It discusses causes of slope failure such as gravitational forces, seepage, erosion, and earthquakes. Methods of slope stability analysis are described including infinite slope analysis, finite slope analysis using wedge failure, friction circle, and Swedish circle methods. Factors of safety are defined with respect to shear strength, cohesion, and friction. The aims of slope stability analysis are to assess stability, understand failure mechanisms, and design preventive measures.
DESTRUCTIVE AND NON-DESTRUCTIVE TEST OF CONCRETEKaran Patel
The standard method of evaluating the quality of concrete in buildings or structures is to test specimens cast simultaneously for compressive, flexural and tensile strengths.
The main disadvantages are that results are not obtained immediately; that concrete in specimens may differ from that in the actual structure as a result of different curing and compaction conditions; and that strength properties of a concrete specimen depend on its size and shape.
Although there can be no direct measurement of the strength properties of structural concrete for the simple reason that strength determination involves destructive stresses, several non- destructive methods of assessment have been developed.
Consolidation is the process where water drains from saturated soil pores, transferring the load from water to soil particles and causing volume change. There are three types of consolidation: immediate, primary, and secondary. One-dimensional consolidation assumes vertical drainage, making the process primarily vertical. Terzaghi's theory of one-dimensional consolidation models this using parameters like permeability, compressibility, and effective stress. The coefficient of consolidation describes the rate of compression, while compression and swelling indices characterize the void ratio-effective stress relationship. The oedometer test experimentally determines consolidation properties from soil specimen compression under incremental loads.
This document provides an overview of slope stability and analysis. It defines different types of slopes as natural, man-made, infinite and finite. Common causes of slope failure like erosion, seepage, drawdown, rainfall, earthquakes and external loading are described. Key terms used in slope stability are defined, including slip zone, slip plane, sliding mass and slope angle. Types of slope failures are identified as face/slope failure, toe failure and base failure. Methods for analyzing finite slope stability, like Swedish circle method, Bishop's simplified method and Taylor's stability number are introduced. Infinite slope analysis is described for cohesionless, cohesive and cohesive-frictional soils. Example tutorial problems on slope stability calculations are
This document discusses the consolidation of soil. It defines important terms like compression, compressibility, and consolidation. It outlines the differences between compaction and consolidation. The importance of consolidation theory is that it provides information on total settlement, time for settlement, and types of settlement. Terzaghi's spring analogy is described to explain the consolidation process. A one-dimensional consolidation test procedure is outlined. Important definitions related to consolidation like compression index, swelling index, and coefficients are provided. The document also discusses normally, under, and over consolidated soils and how to determine preconsolidation pressure. Terzaghi's one-dimensional consolidation theory and solution are presented. Methods to determine degree of consolidation and coefficient of consolidation from laboratory test data are
The document provides an introduction to soil mechanics and soil types. It defines soil mechanics as the branch of engineering that deals with the properties and behavior of soil. It discusses the different types of soils based on their geological origin such as glacial soil, residual soil, alluvial soil, and aeolian soil. It also classifies soils based on engineering properties such as clay, silt, sand, gravel, cobbles, and boulders. The key factors that influence the engineering behavior of soils like particle size, shape, mineral composition are also highlighted.
1. This document provides information about vertical stresses below applied loads on the ground surface. It discusses theories of elasticity and how soils can be treated as quasi-elastic materials under limited loading conditions.
2. It presents Boussinesq's formula and Westergaard's modified formula for calculating vertical stresses below a point load on the ground surface. It also discusses pressure isobars and how they can be used to determine a significant depth below applied loads.
3. The document concludes with examples of calculating vertical stresses using Boussinesq's and Westergaard's formulas, and an example of determining pressure isobars and significant depth. Homework assignments are also provided applying the stress calculation methods.
This document discusses earth pressure at rest for foundation engineering. It defines the coefficient of earth pressure at rest (Ko) as the ratio of horizontal to vertical stress. Using Ko, it describes how to calculate the lateral pressure at rest (Po) and total lateral pressure (ph) at a given depth, accounting for factors like a water table. Diagrams show how the pressure distribution forms a triangle against a retaining wall, with the maximum pressure at the bottom. Equations are provided to calculate the pressure and total force per unit length of the wall for dry, saturated, and water table conditions.
PLATE LOAD TEST
PRESUMPTIVE SAFE BEARING CACACITY
PLATE LOAD TEST APPARATUS / EQUIPMENT
PLATE LOAD TEST PROCEDURE
CALCULATION OF BEARING CAPACITY FROM PLATE LOAD TEST
For vedo link
Https://youtu.be/BUMd7CKcBV8
Class notes of Geotechnical Engineering course I used to teach at UET Lahore. Feel free to download the slide show.
Anyone looking to modify these files and use them for their own teaching purposes can contact me directly to get hold of editable version.
Bearing capacity of shallow foundations by abhishek sharma ABHISHEK SHARMA
elements you should know about bearing capacity of shallow foundations are included in it. various indian standards are also used. Bearing capacity theories by various researchers are also included. numericals from GATE CE and ESE CE are also included.
This document provides an overview of the course "Foundation Engineering" including:
- The course contents which covers topics like shallow foundations, deep foundations, retaining structures, and soil improvements across 10 chapters.
- The examination and grading system with 80 marks for final exam, 20 marks for internal assessment, and 25 marks for practical.
- An introduction to foundation engineering including different types of foundations, factors influencing foundation choice, and the general requirements for shallow foundations.
- There are four main methods to measure the load carrying capacity of piles: static methods, dynamic formulas, in-situ penetration tests, and pile load tests.
- The ultimate load capacity (Qu) of an individual pile or pile group equals the sum of the point resistance (Qp) at the pile tip and the shaft resistance (Qs) developed along the pile shaft through friction between the soil and pile.
- Meyerhof's method is commonly used to calculate Qp in sand based on the effective vertical pressure at the pile tip multiplied by the bearing capacity factor Nq.
TERZAGHI’S BEARING CAPACITY THEORY
DERIVATION OF EQUATION TERZAGHI’S BEARING CAPACITY THEORY
TERZAGHI’S BEARING CAPACITY FACTORS
Download vedio link
https://youtu.be/imy61hU0_yo
This document discusses reinforced soil retaining walls. It provides an overview of the components and construction process. Reinforced soil uses soil reinforced with linear strips that can bear large tensile stresses. Retaining walls hold earth and other materials in a vertical position. Reinforced soil retaining walls were developed from the idea of reinforcing sandcastles with pine needles. They have load transfer mechanisms that use friction between the soil and reinforcement to resist shear stresses. Components include soil, facing panels, reinforcement and geosynthetics. Construction involves compacting layers of backfill soil and placing horizontal reinforcement strips. Reinforced soil retaining walls provide benefits like reduced lateral thrust, thin wall elements, simple and fast construction, and seismic resistance.
This document provides an overview of foundation engineering. It begins with definitions of foundations and footings, noting that foundations transmit loads from the superstructure to the underlying soil. It then discusses different types of shallow foundations, including isolated, strip, combined, and raft foundations. Deep foundations like pile foundations are also introduced. The document covers footing design considerations such as depth, spacing, and stability. It explains bearing capacity and failure modes in soil. In summary, the document provides a high-level introduction to foundation types, design requirements, and bearing capacity fundamentals.
The document discusses soil properties testing and investigation methods. It outlines the typical project sequence which includes site research, field reconnaissance, exploration, laboratory investigations, and reporting. Common objectives are to identify surface conditions, determine subsurface soil profiles, locate groundwater, recover samples, and conduct lab/field testing. Field tests discussed include standard penetration testing, cone penetration testing, vane shear testing, and plate load testing. Laboratory tests examine properties like moisture content, density, plasticity, gradation, shear strength, consolidation, and swelling. The results of these investigations and tests are used to evaluate soil bearing capacity and foundation design.
This document provides lecture notes on slope stability analysis. It begins with an introduction to slopes, defining slopes and discussing natural and man-made slope failures. It then discusses various methods of slope stability analysis, including infinite slope analysis for cohesionless, cohesive, and cohesive-frictional soils, considering factors like seepage. Finite slope analysis methods are also introduced, including total stress analysis for cohesive and c-φ soils. Key concepts covered include factor of safety, failure surfaces, driving and restoring moments. Factors affecting slope stability like rainfall, earthquakes, and tension cracks are also summarized.
This document discusses different methods of prestressing concrete, including pretensioning and post-tensioning. Pretensioning involves stressing steel tendons before placing concrete around them, while post-tensioning involves stressing tendons after the concrete has cured using hydraulic jacks. Post-tensioning allows for longer spans, thinner slabs, and more architectural freedom compared to conventional reinforced concrete or pretensioned concrete. Common applications of post-tensioning include parking structures, bridges, and building floors and roofs.
Class notes of Geotechnical Engineering course I used to teach at UET Lahore. Feel free to download the slide show.
Anyone looking to modify these files and use them for their own teaching purposes can contact me directly to get hold of editable version.
This document will help you learn an introductory part and some detailed information on Shallow Foundations. As I am presenting this document to you I wish you all a Happy learning arena. It is highly recommended for students taking a bachelor degree in Civil Engineering, also it is a good document for students who are doing final touches for their examinations.
This document discusses slope stability and different types of slope failures including translational and rotational. It describes factors that affect slope stability such as erosion, water seepage, earthquakes, and gravity. Methods for analyzing slope stability are presented, including infinite slope analysis, Culmann's method, friction circle method, method of slices, Bishop's method, and Spencer's method. The key parameters in analyzing slope stability are the factor of safety and stability number.
lecturenote_1463116827CHAPTER-II-BEARING CAPACITY OF FOUNDATION SOIL.pdf2cd
The document discusses bearing capacity of soils and methods to calculate the ultimate and safe bearing capacities of different types of foundations. It defines key terms like ultimate, gross, net and safe bearing capacities. It describes Terzaghi's, Meyerhof's and Skempton's methods to calculate the bearing capacity based on the soil properties and foundation geometry. It provides examples to calculate the ultimate and safe bearing capacities of strip, square, circular and rectangular foundations in cohesive and cohesionless soils using these methods.
Subsoil exploration involves collecting soil data through field and laboratory investigations to assess soil properties at a site. The main objectives are to determine the nature, depth, thickness, and extent of soil strata as well as groundwater conditions and engineering properties. Methods include test pits, borings using augers or drilling, in-situ tests like SPT and CPT, and geophysical methods. Proper planning, execution, and reporting of the investigation are needed to provide reliable data to aid foundation design.
This document discusses the consolidation of soil. It defines important terms like compression, compressibility, and consolidation. It outlines the differences between compaction and consolidation. The importance of consolidation theory is that it provides information on total settlement, time for settlement, and types of settlement. Terzaghi's spring analogy is described to explain the consolidation process. A one-dimensional consolidation test procedure is outlined. Important definitions related to consolidation like compression index, swelling index, and coefficients are provided. The document also discusses normally, under, and over consolidated soils and how to determine preconsolidation pressure. Terzaghi's one-dimensional consolidation theory and solution are presented. Methods to determine degree of consolidation and coefficient of consolidation from laboratory test data are
The document provides an introduction to soil mechanics and soil types. It defines soil mechanics as the branch of engineering that deals with the properties and behavior of soil. It discusses the different types of soils based on their geological origin such as glacial soil, residual soil, alluvial soil, and aeolian soil. It also classifies soils based on engineering properties such as clay, silt, sand, gravel, cobbles, and boulders. The key factors that influence the engineering behavior of soils like particle size, shape, mineral composition are also highlighted.
1. This document provides information about vertical stresses below applied loads on the ground surface. It discusses theories of elasticity and how soils can be treated as quasi-elastic materials under limited loading conditions.
2. It presents Boussinesq's formula and Westergaard's modified formula for calculating vertical stresses below a point load on the ground surface. It also discusses pressure isobars and how they can be used to determine a significant depth below applied loads.
3. The document concludes with examples of calculating vertical stresses using Boussinesq's and Westergaard's formulas, and an example of determining pressure isobars and significant depth. Homework assignments are also provided applying the stress calculation methods.
This document discusses earth pressure at rest for foundation engineering. It defines the coefficient of earth pressure at rest (Ko) as the ratio of horizontal to vertical stress. Using Ko, it describes how to calculate the lateral pressure at rest (Po) and total lateral pressure (ph) at a given depth, accounting for factors like a water table. Diagrams show how the pressure distribution forms a triangle against a retaining wall, with the maximum pressure at the bottom. Equations are provided to calculate the pressure and total force per unit length of the wall for dry, saturated, and water table conditions.
PLATE LOAD TEST
PRESUMPTIVE SAFE BEARING CACACITY
PLATE LOAD TEST APPARATUS / EQUIPMENT
PLATE LOAD TEST PROCEDURE
CALCULATION OF BEARING CAPACITY FROM PLATE LOAD TEST
For vedo link
Https://youtu.be/BUMd7CKcBV8
Class notes of Geotechnical Engineering course I used to teach at UET Lahore. Feel free to download the slide show.
Anyone looking to modify these files and use them for their own teaching purposes can contact me directly to get hold of editable version.
Bearing capacity of shallow foundations by abhishek sharma ABHISHEK SHARMA
elements you should know about bearing capacity of shallow foundations are included in it. various indian standards are also used. Bearing capacity theories by various researchers are also included. numericals from GATE CE and ESE CE are also included.
This document provides an overview of the course "Foundation Engineering" including:
- The course contents which covers topics like shallow foundations, deep foundations, retaining structures, and soil improvements across 10 chapters.
- The examination and grading system with 80 marks for final exam, 20 marks for internal assessment, and 25 marks for practical.
- An introduction to foundation engineering including different types of foundations, factors influencing foundation choice, and the general requirements for shallow foundations.
- There are four main methods to measure the load carrying capacity of piles: static methods, dynamic formulas, in-situ penetration tests, and pile load tests.
- The ultimate load capacity (Qu) of an individual pile or pile group equals the sum of the point resistance (Qp) at the pile tip and the shaft resistance (Qs) developed along the pile shaft through friction between the soil and pile.
- Meyerhof's method is commonly used to calculate Qp in sand based on the effective vertical pressure at the pile tip multiplied by the bearing capacity factor Nq.
TERZAGHI’S BEARING CAPACITY THEORY
DERIVATION OF EQUATION TERZAGHI’S BEARING CAPACITY THEORY
TERZAGHI’S BEARING CAPACITY FACTORS
Download vedio link
https://youtu.be/imy61hU0_yo
This document discusses reinforced soil retaining walls. It provides an overview of the components and construction process. Reinforced soil uses soil reinforced with linear strips that can bear large tensile stresses. Retaining walls hold earth and other materials in a vertical position. Reinforced soil retaining walls were developed from the idea of reinforcing sandcastles with pine needles. They have load transfer mechanisms that use friction between the soil and reinforcement to resist shear stresses. Components include soil, facing panels, reinforcement and geosynthetics. Construction involves compacting layers of backfill soil and placing horizontal reinforcement strips. Reinforced soil retaining walls provide benefits like reduced lateral thrust, thin wall elements, simple and fast construction, and seismic resistance.
This document provides an overview of foundation engineering. It begins with definitions of foundations and footings, noting that foundations transmit loads from the superstructure to the underlying soil. It then discusses different types of shallow foundations, including isolated, strip, combined, and raft foundations. Deep foundations like pile foundations are also introduced. The document covers footing design considerations such as depth, spacing, and stability. It explains bearing capacity and failure modes in soil. In summary, the document provides a high-level introduction to foundation types, design requirements, and bearing capacity fundamentals.
The document discusses soil properties testing and investigation methods. It outlines the typical project sequence which includes site research, field reconnaissance, exploration, laboratory investigations, and reporting. Common objectives are to identify surface conditions, determine subsurface soil profiles, locate groundwater, recover samples, and conduct lab/field testing. Field tests discussed include standard penetration testing, cone penetration testing, vane shear testing, and plate load testing. Laboratory tests examine properties like moisture content, density, plasticity, gradation, shear strength, consolidation, and swelling. The results of these investigations and tests are used to evaluate soil bearing capacity and foundation design.
This document provides lecture notes on slope stability analysis. It begins with an introduction to slopes, defining slopes and discussing natural and man-made slope failures. It then discusses various methods of slope stability analysis, including infinite slope analysis for cohesionless, cohesive, and cohesive-frictional soils, considering factors like seepage. Finite slope analysis methods are also introduced, including total stress analysis for cohesive and c-φ soils. Key concepts covered include factor of safety, failure surfaces, driving and restoring moments. Factors affecting slope stability like rainfall, earthquakes, and tension cracks are also summarized.
This document discusses different methods of prestressing concrete, including pretensioning and post-tensioning. Pretensioning involves stressing steel tendons before placing concrete around them, while post-tensioning involves stressing tendons after the concrete has cured using hydraulic jacks. Post-tensioning allows for longer spans, thinner slabs, and more architectural freedom compared to conventional reinforced concrete or pretensioned concrete. Common applications of post-tensioning include parking structures, bridges, and building floors and roofs.
Class notes of Geotechnical Engineering course I used to teach at UET Lahore. Feel free to download the slide show.
Anyone looking to modify these files and use them for their own teaching purposes can contact me directly to get hold of editable version.
This document will help you learn an introductory part and some detailed information on Shallow Foundations. As I am presenting this document to you I wish you all a Happy learning arena. It is highly recommended for students taking a bachelor degree in Civil Engineering, also it is a good document for students who are doing final touches for their examinations.
This document discusses slope stability and different types of slope failures including translational and rotational. It describes factors that affect slope stability such as erosion, water seepage, earthquakes, and gravity. Methods for analyzing slope stability are presented, including infinite slope analysis, Culmann's method, friction circle method, method of slices, Bishop's method, and Spencer's method. The key parameters in analyzing slope stability are the factor of safety and stability number.
lecturenote_1463116827CHAPTER-II-BEARING CAPACITY OF FOUNDATION SOIL.pdf2cd
The document discusses bearing capacity of soils and methods to calculate the ultimate and safe bearing capacities of different types of foundations. It defines key terms like ultimate, gross, net and safe bearing capacities. It describes Terzaghi's, Meyerhof's and Skempton's methods to calculate the bearing capacity based on the soil properties and foundation geometry. It provides examples to calculate the ultimate and safe bearing capacities of strip, square, circular and rectangular foundations in cohesive and cohesionless soils using these methods.
Subsoil exploration involves collecting soil data through field and laboratory investigations to assess soil properties at a site. The main objectives are to determine the nature, depth, thickness, and extent of soil strata as well as groundwater conditions and engineering properties. Methods include test pits, borings using augers or drilling, in-situ tests like SPT and CPT, and geophysical methods. Proper planning, execution, and reporting of the investigation are needed to provide reliable data to aid foundation design.
This document summarizes bearing capacity theory for shallow foundations. It defines key terms like ultimate, net ultimate, and safe bearing capacities. It describes Terzaghi's bearing capacity equation, which considers soil shear strength parameters (c, φ), surcharge loads, and bearing capacity factors (Nc, Nq, Nr). It outlines the failure geometry Terzaghi assumed, with five distinct failure zones. It also distinguishes between general shear, local shear, and punching shear failures based on soil properties and characteristics. Empirical modifications are suggested for local shear failures. Charts summarize the bearing capacity equations for different shaped footings based on experimental results.
The document discusses pavement materials and field evaluations for geotechnical engineering. It covers various field investigation techniques like drilling, test pits, and geophysical testing methods like seismic and electrical resistivity surveys. Seismic techniques measure wave velocities to evaluate subsurface strata properties. Electrical resistivity uses differences in resistivity between soil/rock layers. Subgrade construction principles are also covered, including establishing grade lines, compaction objectives to improve strength and reduce settlements, and factors that control compaction like soil type, water content, and compactive effort.
Applications of Vane Shear Test in Geotechnical soil investigationsAzdeen Najah
The document discusses the results of vane shear tests conducted on soil samples from a site for a proposed 40 km highway near a riverbank. The test results show undrained shear strengths (Cu) below 90 kPa, indicating the need for ground improvement. Recommendations include using geotextiles to separate weak subgrade soils from pavement layers, improving the subgrade quality through compaction or adding aggregates/additives, using geogrid reinforcement in the subgrade and base course, and placing geogrids and concrete on embankment slopes for stability.
This document discusses the bearing capacity of bedrock and soil deposits on slopes. It provides definitions of key terms like ultimate and allowable bearing capacity. It describes various methods for calculating bearing capacity, including equations that account for factors like rock mass quality, joint spacing, slope angle, and soil type. Failure modes like general shear, local shear, and punching shear are also outlined. The document notes how soil deposits form on slopes and factors affecting the stability of soils on steep slopes, both natural and human-related.
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.
Site investigation involves determining the soil layers and properties beneath a proposed structure. It helps select the foundation type and depth, evaluate load capacity, estimate settlement, and identify potential issues. The exploration program uses methods like test pits, auger and wash borings, probing, and geophysics to obtain samples and measure properties. A site investigation includes planning borings and tests, executing fieldwork, and reporting the findings and recommendations.
1. Local soil conditions significantly impact the seismic response of soil-structure systems. Soils exhibit complex non-linear behavior under seismic loading ranging from cyclic mobility to liquefaction and large displacements.
2. Building codes incorporate soil effects on seismic demand through site classifications and amplification factors, but these do not account for liquefaction, topography, or soil-structure interaction.
3. Estimating soil displacements is important for performance-based design, with recent codes prescribing allowances for total and differential displacements on foundations.
Design, seepage analysis and controls of waste dumpsSafdar Ali
1) The document discusses slope stability analysis for external and internal dumps at a mine site. Slope angles, heights, and strength parameters of dump and foundation materials are considered in the analyses.
2) Stability analyses were performed using limit equilibrium methods like Bishop, Janbu, and Morgenstern-Price for slope heights ranging from 30-60m and slope angles from 25-40 degrees. Factors of safety below 1 indicate unstable slopes.
3) Key factors influencing stability include dump geometry, material strengths, groundwater conditions, and seismic forces. Slope/W software was used to model heterogeneous soils and complex conditions.
Pile design summary of ø450, ø600, ø750 and ø900 12, 15 and 20m long -Prakash Rawal
This document provides a calculation of pile design for a cement factory in Nepal to analyze vertical load transfer, lateral shear force, bending moment, and uplift capacity. It summarizes the soil parameters from two borehole investigations, with Borehole 2 found to be more critical. Pile designs are calculated for diameters of 450mm, 600mm, 750mm, and 900mm and lengths of 12m, 15m, and 20m using the GEO5 software. The calculation methodology is described, including determination of soil properties like oedometric modulus. Formulas are provided for calculations of vertical bearing capacity, lateral subgrade modulus, and verification of the pile design. Soil parameters from the three soil layers are also summarized.
This document discusses bearing capacity and shallow foundations. It defines bearing capacity as the maximum average pressure a soil can support before failing. There are two failure criteria: shear failure and settlement. Terzaghi's bearing capacity theory is then explained, with soil divided into three zones. Factors influencing bearing capacity are also listed, such as soil type, foundation properties, water table level, and loading eccentricity. Finally, common bearing capacity determination methods are outlined, including analytical calculations, load tests, and laboratory tests.
Post Earthquack Slope Stability Analysis of Rubble Mound BreakwaterIJERA Editor
Rubble mound breakwaters are structures built mainly of quarried rock. Generally armourstone or artificial concrete armour units are used for the outer armour layer,which should protect the structure againist wave attack. Armour stones and concrete armoure unites in this outer layer are usually placed with care to obtain effective interlocking and consequently better stability
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Site investigation involves determining the soil layers and properties beneath a proposed structure. It helps select the foundation type, evaluate load capacity, estimate settlement, and identify potential issues. The exploration program uses methods like boreholes, test pits, and probes to characterize soil stratification, strength, deformation, and groundwater. Proper planning is needed to obtain reliable data at minimum cost.
Subsoil exploration involves laboratory and field investigations to assess soil properties at a site. It determines the nature, depth, and thickness of soil strata as well as groundwater conditions and engineering properties. Methods include test pits, boreholes using augers or drilling, in-situ tests like SPT and CPT, and geophysical methods such as seismic refraction and electrical resistivity testing. The results are used to select appropriate foundation types and determine bearing capacity.
Raft foundations are used when buildings have heavy loads, compressible soil, or require minimal differential settlement. A raft foundation is a continuous concrete slab that supports all building columns. It can be designed using either a rigid or flexible approach. The rigid approach assumes the raft bridges soil variations, while the flexible approach models soil-structure interaction. Key considerations for raft design include bearing capacity, settlement, stress distribution, and structural component sizing.
1. Foundation settlement includes immediate, primary consolidation, and secondary consolidation settlements. Immediate settlement occurs after construction, primary consolidation is due to pore pressure dissipation and water expulsion, and secondary consolidation is long-term rearrangement of soil particles under constant effective stress.
2. Vertical stress distribution in soil must be determined to calculate settlement. Several methods are described to calculate stress, including Boussinesq analysis and Westergaard's method. Simplified methods and charts like Newmark's can also be used.
3. Settlement is calculated using soil properties like compression index, preconsolidation pressure, and void ratio. Methods are described for cohesive and cohesionless soils using parameters from tests like
Similar to Advanced foundation design(nce 011) (20)
This document discusses the typical layers of a flexible pavement. It begins by describing seal coat, tack coat, and prime coat layers. It then outlines the layers of a carriageway from bottom to top: earth work, granular sub base, wet mix macadam, bituminous macadam, bituminous concrete. Details are provided on the materials and construction procedures for some of these layers. The document also discusses cement concrete pavements and their advantages over flexible pavements.
Pavement refers to durable surface materials laid down on areas for vehicular or foot traffic like roads and walkways. There are two main types: flexible pavement made of materials like asphalt, and rigid pavement made of concrete. Flexible pavement has lower initial costs but requires more maintenance, while rigid pavement has higher initial costs but lasts longer with less maintenance. The document discusses the layers, materials, design processes, and testing methods used for both flexible and rigid pavements.
Traffic engineering is the science of measuring and studying traffic flow in order to safely and efficiently manage vehicle and people movement. The objectives of traffic engineering are to achieve free flowing traffic and reduce accidents. Some key aspects of traffic engineering include conducting traffic studies to analyze characteristics, planning and designing road geometry, implementing traffic control devices, and educating road users. Traffic studies measure factors like volume, speed, origin-destination, and flow characteristics to determine appropriate road facilities and control measures. Understanding traffic patterns helps engineers design efficient transportation systems.
This document discusses the key concepts of geometric design of highways. It defines geometric design as dealing with the visible dimensions and layout of a highway. The goals of geometric design are to maximize comfort, safety and economy while providing efficient traffic operation. Some key factors that influence geometric design are design speed, topography, traffic, environment and cost. The document outlines various elements of highway cross-sections including the carriageway, shoulders, roadway width, right of way and median. It also discusses horizontal and vertical alignment, types of alignment, and considerations for factors like gradient, sight distance and curves.
This document provides an overview of transportation engineering and the various modes of transportation. It focuses on road transportation and the historical development of roads in India. The key modes discussed are land (road and rail), water, and air transportation. For road transportation specifically, it outlines the major classifications of highways in India and the historical milestones in road development, including committees established and plans implemented over time to improve the road network.
This document provides an introduction to aerial photography and remote sensing. It discusses key topics such as:
- The basic concepts and terminology of aerial photography, including flight height, focal length, scale, and camera geometry.
- The different types of aerial photographs, including vertical, low-oblique, and high-oblique views.
- Factors that influence photo quality, such as weather conditions, camera equipment, and processing methods.
- The principles of photogrammetry and stereo viewing, including parallax and stereoscopes.
- Common image interpretation elements like shape, size, tone, texture, pattern, site, association, and shadows.
- An overview of remote sensing concepts like
Mechatronics is a multidisciplinary field that refers to the skill sets needed in the contemporary, advanced automated manufacturing industry. At the intersection of mechanics, electronics, and computing, mechatronics specialists create simpler, smarter systems. Mechatronics is an essential foundation for the expected growth in automation and manufacturing.
Mechatronics deals with robotics, control systems, and electro-mechanical systems.
Open Channel Flow: fluid flow with a free surfaceIndrajeet sahu
Open Channel Flow: This topic focuses on fluid flow with a free surface, such as in rivers, canals, and drainage ditches. Key concepts include the classification of flow types (steady vs. unsteady, uniform vs. non-uniform), hydraulic radius, flow resistance, Manning's equation, critical flow conditions, and energy and momentum principles. It also covers flow measurement techniques, gradually varied flow analysis, and the design of open channels. Understanding these principles is vital for effective water resource management and engineering applications.
Optimizing Gradle Builds - Gradle DPE Tour Berlin 2024Sinan KOZAK
Sinan from the Delivery Hero mobile infrastructure engineering team shares a deep dive into performance acceleration with Gradle build cache optimizations. Sinan shares their journey into solving complex build-cache problems that affect Gradle builds. By understanding the challenges and solutions found in our journey, we aim to demonstrate the possibilities for faster builds. The case study reveals how overlapping outputs and cache misconfigurations led to significant increases in build times, especially as the project scaled up with numerous modules using Paparazzi tests. The journey from diagnosing to defeating cache issues offers invaluable lessons on maintaining cache integrity without sacrificing functionality.
Home security is of paramount importance in today's world, where we rely more on technology, home
security is crucial. Using technology to make homes safer and easier to control from anywhere is
important. Home security is important for the occupant’s safety. In this paper, we came up with a low cost,
AI based model home security system. The system has a user-friendly interface, allowing users to start
model training and face detection with simple keyboard commands. Our goal is to introduce an innovative
home security system using facial recognition technology. Unlike traditional systems, this system trains
and saves images of friends and family members. The system scans this folder to recognize familiar faces
and provides real-time monitoring. If an unfamiliar face is detected, it promptly sends an email alert,
ensuring a proactive response to potential security threats.
Prediction of Electrical Energy Efficiency Using Information on Consumer's Ac...PriyankaKilaniya
Energy efficiency has been important since the latter part of the last century. The main object of this survey is to determine the energy efficiency knowledge among consumers. Two separate districts in Bangladesh are selected to conduct the survey on households and showrooms about the energy and seller also. The survey uses the data to find some regression equations from which it is easy to predict energy efficiency knowledge. The data is analyzed and calculated based on five important criteria. The initial target was to find some factors that help predict a person's energy efficiency knowledge. From the survey, it is found that the energy efficiency awareness among the people of our country is very low. Relationships between household energy use behaviors are estimated using a unique dataset of about 40 households and 20 showrooms in Bangladesh's Chapainawabganj and Bagerhat districts. Knowledge of energy consumption and energy efficiency technology options is found to be associated with household use of energy conservation practices. Household characteristics also influence household energy use behavior. Younger household cohorts are more likely to adopt energy-efficient technologies and energy conservation practices and place primary importance on energy saving for environmental reasons. Education also influences attitudes toward energy conservation in Bangladesh. Low-education households indicate they primarily save electricity for the environment while high-education households indicate they are motivated by environmental concerns.
Use PyCharm for remote debugging of WSL on a Windo cf5c162d672e4e58b4dde5d797...shadow0702a
This document serves as a comprehensive step-by-step guide on how to effectively use PyCharm for remote debugging of the Windows Subsystem for Linux (WSL) on a local Windows machine. It meticulously outlines several critical steps in the process, starting with the crucial task of enabling permissions, followed by the installation and configuration of WSL.
The guide then proceeds to explain how to set up the SSH service within the WSL environment, an integral part of the process. Alongside this, it also provides detailed instructions on how to modify the inbound rules of the Windows firewall to facilitate the process, ensuring that there are no connectivity issues that could potentially hinder the debugging process.
The document further emphasizes on the importance of checking the connection between the Windows and WSL environments, providing instructions on how to ensure that the connection is optimal and ready for remote debugging.
It also offers an in-depth guide on how to configure the WSL interpreter and files within the PyCharm environment. This is essential for ensuring that the debugging process is set up correctly and that the program can be run effectively within the WSL terminal.
Additionally, the document provides guidance on how to set up breakpoints for debugging, a fundamental aspect of the debugging process which allows the developer to stop the execution of their code at certain points and inspect their program at those stages.
Finally, the document concludes by providing a link to a reference blog. This blog offers additional information and guidance on configuring the remote Python interpreter in PyCharm, providing the reader with a well-rounded understanding of the process.
Software Engineering and Project Management - Introduction, Modeling Concepts...Prakhyath Rai
Introduction, Modeling Concepts and Class Modeling: What is Object orientation? What is OO development? OO Themes; Evidence for usefulness of OO development; OO modeling history. Modeling
as Design technique: Modeling, abstraction, The Three models. Class Modeling: Object and Class Concept, Link and associations concepts, Generalization and Inheritance, A sample class model, Navigation of class models, and UML diagrams
Building the Analysis Models: Requirement Analysis, Analysis Model Approaches, Data modeling Concepts, Object Oriented Analysis, Scenario-Based Modeling, Flow-Oriented Modeling, class Based Modeling, Creating a Behavioral Model.
3. Soils Investigation
Determination of surface and subsurface soil
conditions and features in an area of proposed
construction that may influence the design and
construction and address expected post construction
problems.
4. Soils Investigation contd.
Required to evaluate an area for the construction of
a project or evaluate local material as a construction
material
Soil Investigation
Field Sampling and Testing
Laboratory Analysis
Report preparation
Planning and evaluation of field work are aided by
knowledge of the mechanics of soil deposit’s
formation
5. Soils Investigation contd.
Soil grains are the result of weathering of bedrock
physical weathering
granular soil types (gravel, sand, silt)
chemical weathering
clays
Soil deposits
residual- product of weathering the original
bedrock
transported- moved from their place of origin
6. Soils Investigation contd.
Transportation agents
Rivers and streams
gravel sand silt deposited as a fn (water
velocity)
Lakes
clays and silts settling out
Wind
sand dunes and loess deposits (silt particles)
7. Soils Investigation contd.
Glacier soil deposits
tills (mixture of gravel sand silt clay)
material that has been shoved forward or
picked up from an advancing glacier
this material is deposited when a glacier stops
or retreats as it melts
fluvial deposits associated with glaciers
clays from glacier lakes
marine clays deposited from salt water
sorted gravel, sand and silt from glacier streams
8. Requirement of Soils Investigation
Field Investigation Techniques
determine bearing capacity for foundations
determine water resources
find aggregate deposits (road construction)
estimate infiltration and seepage rates
assess land use capabilities
Information required
depth, thickness, properties of each soil layer
location of groundwater table
depth to bedrock
9. Soils Investigation contd.
Subsurface Investigation
Geophysical methods
seismic or electrical-variations in the speed of sound
waves or electrical resistivity of soil formations
Test pits or trenches
shallow depths only
Hand Augers
shallow depths only
Boring test holes and sampling with drill rigs
principal method for detailed soil investigations
10. GEOPHYSICAL METHOD
Although boring and test pits provide definite results but they are
time consuming and expensive.
Subsurface conditions are known only at the bore or test pit
location.
The subsurface conditions between the boring need to be
interpolated or estimated.
Geophysical methods are more quick and cheaper.
They provide thorough coverage of the entire area.
results of Geophysical testing however are less definitive and
require subjective interpretation.
both methods are important. In case geophysical testing in major
in scope, few borings and sampling will be required for accurate
determination of soil properties.
If boring is major in scope then few geophysical lines will be
required to know the conditions in-between the borings.
11. Geophysical Techniques Indirect Methods
Ground Penetrating Radar
(GPR)
Electromagnetic (EM)
Magnetic
Utility Locating
Seismic
Electrical Resistivity
Gravity
Very Low Frequency (VLF)
12. Geophysical Techniques Indirect Methods
Advantages
Non-Destructive
Cost Effective
Provides Preliminary or
Supplemental
Information
14. Soil Resistivity Method
Resisitivity (ohm-m) is an electrical property. It is
the reciprocal of conductivity
Arrays of electrodes used to measure changes in
potential.
Evaluate changes in soil types and variations in
pore fluids
Used to map faults, karst features (caves,
sinkholes), stratigraphy, contaminant plumes.
19. Westergaard’s Theory of Stress
Westergaard developed a solution to determine
distribution of stress due to point load in soils
composed of thin layer of granular material that
partially prevent lateral deformation of the soil.
20. Westergaard’s Theory of Stress
2/322z
z
r
21
1
z
P
2/32
2
2z
z
r
a
1
z2
a.P
• Point Load
22
21
a
22. Shallow foundations:
Where the ratio of embedment depth to min plan
dimension is less or equal to 2.5
Embedment depth is the depth below the ground surface
where the base of foundation rests.
plain concrete foundation,
stepped reinforced concrete foundation,
reinforced concrete rectangular foundation
reinforced concrete wall foundation.
Shallow Foundation
23. Steps in Selection of Foundation Types
1 Obtain the required information concerning the nature of the
superstructure and the loads to be transmitted to the foundation.
2. Obtain the subsurface soil conditions.
3. Explore the possibility of constructing any one of the types of foundation
under the existing conditions by taking into account (i) the bearing
capacity of the soil to carry the required load, and (ii) the adverse effects
on the structure due to differential settlements. Eliminate in this way, the
unsuitable types.
4. Once one or two types of foundation are selected on the basis of
preliminary studies, make more detailed studies. These studies may require
more accurate determination of loads, subsurface conditions and footing
sizes. It may also be necessary to make more refined estimates of
settlement in order to predict the behavior of the structure.
5. Estimate the cost of each of the promising types of foundation, and
choose the type that represents the most acceptable compromise between
performance and cost.
25. Shallow Foundation
Strip Footings to support wall loads
Rectangular and Trapezoidal Footings for two
columns (combined footing) or machine base
26. Raft or Mat Foundation
To lower the bearing pressure and reduce
differential settlement on soils with low bearing
capacity or erratic or variable conditions
27. Ultimate Bearing Capacity, qf
The least pressure that would cause shear
failure of supporting soil immediately below
and adjacent to a foundation
28. Modes of Failure(General Shear Failure)
on low compressibility
(dense or stiff) soils
plastic equilibrium
throughout support and
adjacent soil masses
heaving on both sides
of foundation
final slip (movement of
soil) on one side only
causing structure to tilt
29. Modes of Failure (Local Shear Failure)
on highly compressible
soils
only partial development
of plastic equilibrium
only slight heaving on
sides
significant compression of
soil under footing but no
tilting
30. Modes of Failure (Punching Shear Failure)
on loose, uncompacted
soils
vertical shearing around
edges of footing
high compression of soil
under footing, hence large
settlements
no heaving, no tilting
31. Assumptions for Terzaghi's Method
Depth of foundation is less than or equal to its width
No sliding occurs between foundation and soil (rough
foundation)
Soil beneath foundation is homogeneous semi
infinite mass
Mohr-Coulomb model for soil
General shear failure mode is the governing
mode (but not the only mode)
32. Assumptions for Terzaghi's Method
No soil consolidation occurs
Foundation is very rigid relative to the soil
Soil above bottom of foundation has no shear
strength; is only a surcharge load against the
overturning load
Applied load is compressive and applied vertically to
the centroid of the foundation
No applied moments present
33. Terzaghi’s Bearing Capacity Equation
Neglecting the shear strength
of the soil above depth D
implies that this soil is a
surcharge: qo= γD
Terzaghi’s general equation:
qf = 0.5γBNγ + cNc + γDNq
38. Other Factors
For continuous footing,
s = 1
For perpendicular load,
i = 1
For level foundation,
b =1
For level ground,
g =1
Need to compute factors
Bearing Capacity Factor N,
Depth Factor d
39. General Shear Failure of Footings (Ultimate
Bearing Capacity)
qccf DNSNcSNγBq )()(5.0
)45(tan 2
2)tan(
eNq
)cot()1( qc NN
)4.1tan()1( qNN
FOOTING TYPE Sγ Sc
Strip 1.0 1.0
Square 0.8 1.2
Circular 1.6 1.2
Rectangular 1-0.2(B/L) 1+0.2(B/L)
theory was developed
for strip footings
To adapt square, circular
and rectangular shapes,
Terzaghi & Peck
developed shape factors
here which are still
widely used today:
40. Settlement
Immediate Settlement: Occurs
immediately after the construction.
This is computed using elasticity
theory (Important for Granular soil)
Primary Consolidation: Due to gradual
dissipation of pore pressure induced
by external loading and consequently
expulsion of water from the soil mass,
hence volume change. (Important for
Inorganic clays)
Secondary Consolidation: Occurs at
constant effective stress with volume
change due to rearrangement of
particles. (Important for Organic soils)
46. Primary Consolidation
Expulsion of water from soils accompanied by
increase in effective stress and strength
Amount can be reasonably estimated based on lab
data, but rate is often poorly estimated
47. Consolidation Settlement
This method makes use of the results of the conventional
oedometer test where the consolidation parameters of the
soil are measured.
To compute the stress changes within the soil mass. The stress
changes are computed using a Boussinesq type approach
assuming elasticity.
The important parameter for consolidation settlement
calculation is the net effective stress change in the soil.
Usually the settlements are calculated for the soil divided into
a number of sub-layers and the final total settlement is the
sum of individual sub-layer settlements
49. Secondary Consolidation
At the end of primary settlement, settlement may
continue to develop due to the plastic deformation
(creep) of the soil.
The stage of consolidation is called secondary
consolidation.
51. Deep Foundation
Deep Foundations are those -
in which the depth of the foundation is very large
in comparison to its width.
Which are not constructed by ordinary methods
of open pit excavations.
52. When Used?
In cases where -
The strata of good bearing capacity is not available near
the ground
The space is restricted to allow for spread footings
In these cases the foundation of the structure has to be taken
deep with the purpose of attaining a bearing stratum which is
suitable and which ensures stability and durability of a
structure.
The bearing stratum is not the only case. There may be many
other cases. For example, the foundation for a bridge pier
must be placed below the scour depth, although suitable
bearing stratum may exist at a higher level.
53. Pile Foundations
BS8004 defines deep foundation with D>B or D>3m.
Pile foundation always more expensive than shallow
foundation but will overcome problems of soft
surface soils by transferring load to stronger, deeper
stratum, thereby reducing settlements.
Pile resistance is comprised of
end bearing
shaft friction
For many piles only one of these components is
important. This is the basis of a simple classification
54. End Bearing Piles
End bearing pile
rests on a relative
firm soil . The load
of the structure is
transmitted
through the pile
into this firm soil or
rock because the
base of the pile
bears the load of
the structure, this
type of pile is called
end bearing pile
Piles
Soft Soil
Rock
55. Types of Pile
The pile installation procedure varies considerably, and has an
important influence on the subsequent response
Three categories of piles are classified by method of
installation as below:
Large displacement piles
They encompass all solid driven piles including precast
concrete piles, steel or concrete tubes closed at the
lower end
Small displacement piles
They include rolled steel sections such as H-pile and
open-end tubular piles
Replacement piles
They are formed by machine boring, grabbing or hand-
digging.
56. Ultimate capacity of axially load single pile
in soil
Estimated by designer based on soil data and
somewhat empirical procedures. It is common
practice that the pile capacity be verified by pile load
test at an early stage such that design amendment
can be made prior to installation of the project piles.
The satisfactory performance of a pile is, in most
cases, governed by the limiting acceptable
deformation under various loading conditions.
Therefore the settlement should also be checked.
57. Basic Concept
Qu
W
Qs
Qb
The ultimate bearing capacity (Qu )of a pile
may be assessed using soil mechanics
principles. The capacity is assumed to be
the sum of skin friction and end-bearing
resistance, i.e
Qu =Qb+Qs-W ……………………….(1)
Where,
Qu is total pile resistance,
Qb is the end bearing resistance and
Qs is side friction resistance
General behaviour
Shaft resistance fully mobilized at
small pile movement (<0.01D)
Base resistance mobilized at large
movement (0.1D)
58. End Bearing resistance for Bore pile in
granular soils
Due to the natural of granular soil, the c’ can be assumed
equation to zero. The ultimate end bearing resistance for
bored pile in granular soils may be express in terms of vertical
effective stress, ’v and the bearing capacity factors Nq as :
QB=AB Nq ’v
Nq is generally related to the angle of shearing resistance f’.
For general design purposed, it is suggested that the Nq value
proposed by Berezantze et al (1961) as presented in Figure ??
are used. However, the calculated ultimate base stress should
conservatively be limited to 10Mpa, unless higher values have
been justified by load tests.
59. Shaft Friction Resistance
The ultimate shaft friction stress qs for piles may be expressed in terms of mean
vertical effective stress as :
qs =c’+Ksv’tands
qs =b v’ (when c’=0)
Where,
Ks= coefficient of horizontal pressure which depends on the relative density and
state of soil, method of pile installation, and material length and shape of pile. Ks may
be related to the coefficient of earth pressure at rest,
K0=1-sin
Qv’ = mean vertical effective stress
s’ = angle of friction along pile/soil interface
b = shaft friction coefficient
Qs = pLqs
Where p is the perimeter of the pile and L is the total length of the pile
60. Bored pile in Clays
The ultimate end bearing resistance for piles in clays
is often related to the undrained shear strength, Cu,
as
qB=NcCu
QB=ABNcCu
where,
Nc= 9 when the location of the pile base below
ground surface exceeds fours times the pile diameter
61. Bored pile in Clays
The ultimate shaft friction (qs) for soils in stiff over-
consolidated clays may be estimated on the semi-
empirical method as:
qs=aCu
a is the adhesion factor (range from 0.4 to 0.9)
62. Design of Pile Groups
The efficiency of a pile group is the ratio of the ultimate
capacity of the group to the sum of the candidates of
the individual piles.
ɳg = Qug
nQu
Where:
g = Pile group efficiency.
Qug = Ultimate capacity of the pile group.
n = Number of piles in the pile group.
Qu = Ultimate capacity of each pile in the pile group
63. Design of Pile Groups
The group efficiency may be less than 1 for a pile
group driven into a compressible cohesive soil, or
into a dense cohesionless soil underlain by a weak
cohesive deposit.
The group efficiency in cohesionless soils is generally
greater than 1.
The settlement of a pile group is likely to be many
times greater than that of a single pile carrying the
same load as each pile in the pile group.
66. Group Capacity in Cohesionless Soils
The ultimate axial compression capacity of a pile
group driven in a cohesionless soil may be taken as
the sum of the individual capacities, unless underlain
by a weak deposit, jetted, or predrilled.
If underlain by a weak deposit, the ultimate group
capacity is the lesser of the 1) sum of the individual
pile capacities, or 2) the group capacity against block
failure.
A minimum center-to-center pile spacing of 3
diameters is recommended.
67. Group Capacity in Cohesive Soils
For pile groups in clays with undrained shear strengths
less than 95 kPa (2 ksf), and the cap not in firm contact
with the ground, use a group efficiency ranging from
0.7 for c-t-c spacings of 3 diameters, to 1.0 for c-t-c
spacings of 6 diameters (interpolate in between).
For pile groups in clays with undrained shear strengths
less than 95 kPa (2 ksf), and the cap in firm contact
with the ground, a group efficiency of 1.0 may be used.
For pile groups in clays with undrained shear strengths
greater than 95 kPa (2 ksf), regardless of pile
cap/ground contact, use a group efficiency of 1.0.
68. Group Capacity in Cohesive Soils
Calculate the ultimate pile group capacity against block
failure, and use the lesser capacity.
A center-to-center spacing less than 3 diameters should not
be used
Short-term group efficiencies in cohesive soils 1 to 2 months
after installation may be as low as 0.4 - 0.8 due to high
driving-induced excess porewater pressures (results in
decreased effective stress).
Pile groups in clays which are loaded shortly after pile
installation should consider the reduced short-term group
capacity.
In critical cases, piezometers should be installed to monitor
porewater pressure dissipation with time
69. Settlement of pile group
Block failure of pile groups is generally only a design
consideration for pile groups in soft cohesive soils or
in cohesionless soils underlain by a weak cohesive
layer.
The bearing capacity factor, Nc, for a rectangular pile
group is generally 9.
However, Nc should be calculated for pile groups
with small pile embedment depths and/or large
widths
Nc = 5 [ 1+D/5B ] [ 1+B/5Z ] ≤ 9
71. Expansive Soils
Vertisol Soils, or known as Shrink Swell Soils
The Soil contracts due to its clay minerals and the
structure of the clay allowing water to be imbedded
in-between the clay layers
Process is reversible, and causes contraction of the
soil
72. Characteristics of expansive soils
The expansive properties of soils depend on the
grain size, mineralogy and water content.
The 2:1 sheet smectite group include expansive
monmorillonite clay.
Montmorillonite swell and shrink at different
moisture content
73. Foundation on expansive soil
Foundation is the lowest load-bearing part of
engineering infrastructures, typically below ground
level.
Foundations are affected by engineering properties
and characteristic of the soil.
Engineering problems and type of foundation
support are vital in construction of foundation.
74. Foundation on expansive soil contd.
Foundation on expansive soils is affected by the
behaviour of soil under different moisture content.
The swelling tendency of expansive soils on
foundation can be quantified by the swell potential
and swelling pressure parameters.
The major engineering problem of expansive soils on
foundation is shrink-swelling characteristics of the
soil.
Foundation types that can be utilised on expansive
soils are pile, raft, shallow and caissons foundation.
78. What can be done?
Test soil before building
If expansion is greater then 10 %, it is critical
Remove soil
Mix soil with material that does not expand
Keep consistent soil moisture
Have strong foundations in buildings that can handle
the changes in volume.
79. Engineering solutions
Post-wet and pave the area with bricks or blocks laid
on the plastic membrane.
Total removal of expansive soils.
Under pinning with piles.
Reinforcement of with tie-bars.
Caissons foundation.
80. Well Foundation
Well foundation is the most commonly adopted
foundation for major bridges in India. Since then many
major bridges across wide rivers have been founded on
wells.
Well foundation is preferable to pile foundation when
foundation has to resist large lateral forces.
The construction principles of well foundation are similar
to the conventional wells sunk for underground water.
But relatively rigid and engineering behaviour.
Well foundations have been used in India for centuries.
The famous Taj Mahal at Agra stands on well foundation.
82. Benefits of Well Foundation
Provides massive and solid foundation.
Possible to sink well through boulders,logs of wood
found at depth.
Large section modulus with minimum cross sectional
area is advantageous.
The strata through which well passes is known
exactly.
Well raising and stiening is done in steps so
foundation level can be varied.
Economical to provide it for unstable soil mass
83. Shapes of well foundations
Wells have different shapes and accordingly
they are named as:-
Circular well,
Double D well,
Twin circular well,
Double octagonal well,
Rectangular well.
85. Types of Well Foundation
Open caisson or well
Box Caisson
Pneumatic Caisson
86. Types of Well Foundation
Open caisson or well: The top and bottom of the
caisson is open during construction. It may have any
shape in plan.
Box caisson: It is open at the top but closed at the
bottom.
Pneumatic caisson: It has a working chamber at the
bottom of the caisson which is kept dry by forcing
out water under pressure, thus permitting excavation
under dry conditions.
92. Construction Procedure
Layout
Fabrication of cutting edge.
Well curb.
Construction of stieining.
Island construction
Well Sinking.
Plugging.
Sand filling.
Casting of well cap.
93. Sinking Operations
Erect Cutting Edge.
Erect inside shuttering of curb.
Fix reinforcement for the curb.
Erect outside shuttering of curb.
Concrete the curb and ground it.
Remove the shuttering.
Fix reinforcement in steining
Erect reinforcement for one lift.
94. Sinking Operations Contd.
Concrete the steining.
Dredge inside the well.
Sink the well in stages.
Sinking is done by uniform excavation of material.
Use of water jetting and explosives may be done.
Normally dewatering should not be done.
Tilts must be rectified wherever necessary
95. Precautions
When two wells sunk near each other, they should
be sunk alternately.
Least possible area must be disturbed in vicinity.
In sinking of dumb bell shaped well, excavation must
be done simultaneously.
Dredged material must not be accumulated near
well.
In sinking of two wells through sand, timber logs are
provided between steining.
Care must be taken when cutting edge approaches
junction of strata.
96. Sinking Well Through Clay Strata
It is one of the tough situations to face as well
becomes stationary.
Tilting occurs due to horizontal force by water.
The well becomes vulnerable to tilt if a step is
provided on outside face of the well steining to
reduce
It may lead to a very expensive and time-consuming
affair for attempting to make well straight and
vertical.
97. Measures Adopted
Remove soil in contact with the outside surface of
the well by grabbing to a certain depth.
Continue grabbing much below the cutting edge level
of the well.
Dewatering well results into increasing effective
weight.
Flushing with jet of water on the outside face of well.
By Kentledge loading on the well
98. General Measures for Ease of Sinking.
Appropriate choice of cutting edge and adoption of proper
detailing.
The "Angle iron" cutting edge works well when the well passes
through alluvial soil strata without any hard obstruction.
A "V type" cutting edge is more appropriate in meeting various
obstructive situation provided correct detailing is adopted.
The inclined plate should be stopped about 25 mm above the
bottom tip of vertical plate.
Adequate no. of Borelogs must be taken in the location of each
well.
Presence of very large boulder covering a part of the well at some
depth in the bridge over Brahmaputra at Jogighopa.
Similar type of problems including sudden change of bed profile are
encountered in various rivers in India.
100. Types of slopes
Two Types:
Natural slopes: Due too natural causes
Man made slopes: Cutting and embankments
The slopes whether natural or artificial may be
Infinite slopes
Finite slopes
101. Causes of Failure of Slopes
The important factors that cause instability in a slope
and lead to failure are:
Gravitational force
Force due to seepage water
Erosion of the surface of slopes due to flowing
water
sudden lowering of water adjacent to a slope
Forces due to earthquakes
102. COMMON FEATURES OF SLOPE STABILITY
ANALYSIS METHODS
Safety Factor: F = S/Sm where S = shear strength and
Sm = mobilized shear resistance. F = 1: failure, F > 1:
safety
Shape and location of failure is not known a priori
but assumed (trial and error to find minimum F)
Static equilibrium (equilibrium of forces and
moments on a sliding mass)
Two-dimensional analysis
103. Factors Affecting Slope Failure
Geological discontinuities
Effect of Water
Geotechnical Properties of Material
Mining Methods
State of stress
Geometry slope:
Temperature
Erosion
Seismic effect
Vegetation
104. Types of Rock Slope Failure
Plane failure
Wedge Failure
Toppling failure
Rockfalls
Rotational Failure
105. Rock Slope Stability Analysis: Limit
Equilibrium Method
Planar Failure Analysis
Sliding analysis of a block
Plane failure analysis along a discontinuity
Water is filled in discontinuities
Tension crack present in the upper slope surface
Tension crack present in the slope surface
The tension crack is filled with water with upper slope angle
Effect of rock bolts
Wedge Failure Analysis
Analysis of wedge failure considering only frictional resistance
Analysis of wedge failure with cohesion and friction angle
Toppling Failure Analysis
Kinematics of block toppling failure
Limit equilibrium analysis for toppling failure
Stability analysis of flexural toppling
106. Infinite Slope Analysis
Translational failures along a single plane failure
surface parallel to slope surface
The ratio of depth to failure surface to length of
failure zone is relatively small (<10%)
Applies to surface raveling in granular materials or
slab slides in cohesive materials
Equilibrium of forces on a slice of the sliding mass
along the failure surface is considered
107. Infinite Slope Analysis contd.
F = f(c’, ’, , b, d, u)
F = (c’/ d) secbcosecb + (tan’/tanb)(1-ru sec2b)
where ru = u/d (different ru for seepage parallel to
slope face, seepage emerging, seepage downward,
etc)
For Granular Soil: F = (tan’/tanb)(1-ru sec2b) Dry
Granular Soil (ru = 0): F = (tan’/tanb)
For Cohesive Soil: F decreases with increasing depth
to failure plane; if c is sufficiently large, dc for F = 1
may be large and infinite slope failure may not apply.
108. Finite Slopes: Plane Failure Surface
Translational Block Slides along single plane of
weakness or geological interface
F = c’L + (W cos uL) tan’ / W sin + Fw
110. Method of Slices
Assumes that resultant of side forces on each slice
are collinear and act parallel to failure surface and
therefore cancel each other
F = [cn ln + (Wn cosan - un ln) tann] / Wn sinan
Undrained analysis: F = [cn ln] / Wn sinan
112. Bishop’s Simplified Method
Assumes that resultant of side forces on each slice
act in horizontal direction and therefore vertical side
force components cancel each other
F = [cn bn + (Wn - un bn) tann](1/ma) / Wn sinan
ma = cosan + (sinan tanan)/F
Undrained analysis: F = [cn ln] / Wn sinan
113. Wedge Method
Failure surface consists of two or more planes and
applicable to slope containing several planes of
interfaces and weak layers
Force equilibrium is satisfied
Assumes that resultant of side forces on each slice
either acts horizontally or at varying angles from
horizontal (typically up to 15o)
114. Wedge Analysis
Equilibrium of
Forces in each
slice is considered
to adjust the
inter-slice forces
and balance them
resulting in a
correct solution.
115. Machine Foundations
Machine foundations require a special consideration because they
transmit dynamic loads to soil in addition to static loads due to weight of
foundation, machine and accessories.
The dynamic load due to operation of the machine is generally small
compared to the static weight of machine and the supporting foundation.
In a machine foundation the dynamic load is applied repetitively over a
very long period of time but its magnitude is small and therefore the soil
behaviour is essentially elastic, or else deformation will increase with each
cycle of loading and may become unacceptable.
The amplitude of vibration of a machine at its operating frequency is the
most important
parameter to be determined in designing a machine foundation, in
addition to the natural frequency of a machine foundation soil system.
116. Machine Foundations: Block
Foundation
Block foundation consists of a massive
block of concrete resting directly on soil
or supported on piles or a pedestal
resting on a footing.
If two or more machines of similar type
are to be installed in a shop, these can
profitably be mounted on one continuous
mat.
A block foundation has a large mass and,
therefore, a smaller natural frequency.
The block has large bending and torsional
stiffness and easy to construct. To modify
the block foundation at a later time is
extremely difficult.
117. Machine foundations: Box or Cassion
Foundation
However, if a relatively lighter foundation is
desired, a box or a caisson type foundation may
be provided.
The mass of the foundation is reduced and its
natural frequency increases.
Box or Caisson foundation consists of a hollow
concrete block (can be used as operational
space) that supports the machine on its top.
Hammers may also be mounted on block
foundations, but their details would be quite
different than those for reciprocating machines.
It has high static stiffness just like a plate
foundation and is not easily amenable to
alterations at a later date.
118. Machine foundations: Wall type
Foundation
Steam turbines have complex foundations
that may consist of a system of walls
columns, beams and slabs.
This type is usually adopted for very high-
speed machines requiring large operational
space below for connecting pipes and
additional equipment.
It can be made or either RCC or steel frames.
Although the frame made of steel is easy to
alter at a later date, its behaviour under
dynamic loading is not as good as that of an
RCC frame.
Each element of such a foundation is
relatively flexible as compared to a rigid
block and box or a caisson-type foundation.
119. Design Criteria for Machine Foundations
It should be safe from a bearing capacity failure under static and dynamic
loads,
The settlement must be less than the prescribed ones,
The dynamic amplitudes of the machine-foundation-soil system must be
within the prescribed limits under service conditions.
There should be no resonance, i.e. the natural frequency of the machine-
foundation-soil system should not coincide with the operating frequency
of the machine,
Preferably, the Centre of gravity of the machine should lie in the same
vertical line as the Centre of gravity of the foundation system.
When design criteria (iii) to (v) are satisfied then
the machine itself is not damaged by the vibrations generated,
the structure in which the machine is housed and adjacent structures do not
suffer any vibration induced damage,
performance of machines located in its vicinity is not impaired, and
employees working around the machine are not bothered by the vibrations
120. Vertical Vibrations of a Machine
Foundation
Vertical Vibrations of a Machine Foundation (a) Actual Case (b)
Equivalent model with damping ( c) Model without damping
121. Design of Machine Foundation
In order to calculate the natural frequency and
amplitude of vibrations for a particular machine-
foundation-soil-system, you need to know the local
soil profile and soil characteristics as also the
dynamic loads generated by the machine that are
provided by the manufacturer.
Empirical
Elastic half space method
Linear elastic weightless spring method, and
122. Empirical Method
On such design guideline, rather a rule of thumb was the weight of
the foundation should be at least three to five times the weight of
machine being supported.
There are some empirical formulae available in literature for
estimating the natural frequency, mostly for the vertical mode of
vibration.
In these formulae, it is assumed that a certain part of the soil,
immediately below the foundation, moves as a rigid body along
with the foundation and is called apparent soil mass or in-phase
mass.
For example, D.D.Barken in 1962 suggested that the mass of the
vibrating soil should be between 2/3 to 3/2 times the weight of
foundation and machine.
These guidelines/formulae do not take into account the nature of
subsoil, type of excitation force (harmonic/impact), contact area
and mode of vibration.