Geotechnical investigation of natural slopes is challengeable especially whennatural slopes having higher gradients and access is difficult. Also, it is even more prob-lematic to find the shear strength parameters spatially to evaluate the stability of slopes asmost of the methods available to find the shear strength parameters in the literature areuneconomical or such methods cannot be applied in vegetated slopes. Recently, authorshave conducted a series of in situ investigations based on the newly developed
A New geotechnical method for natural slope exploration and analysisRasika Athapaththu
Geotechnical investigation of natural slopes is challengeable especially when
natural slopes having higher gradients and access is difficult. Also, it is even more prob-
lematic to find the shear strength parameters spatially to evaluate the stability of slopes as
most of the methods available to find the shear strength parameters in the literature are
uneconomical or such methods cannot be applied in vegetated slopes. Recently, authors
have conducted a series of in situ investigations based on the newly developed lightweight
dynamic cone penetrometer to examine its applicability in analyzing the slopes covered
with weathering remnants of decomposed granite. Six patterns were identified based on the
penetration resistance varies with the depth. Spatial variability analysis conducted on
different grid spaces showed that the coefficient of variation of cone resistance varies from
0 to 35 %. Semi-variogram analysis showed that the Spherical Models can be used to
evaluate the spatial variability of weathering remnants of decomposed granite. A series of
laboratory calibration tests based on the lightweight dynamic cone penetration tests and
direct shear tests with pore pressure measurements were conducted at different void ratios
and degrees of saturation. Based on the laboratory calibration test results, a method to
determine the void ratio, e, from the data of qd was presented. Based on this, two formulas
to evaluate the shear strength parameters, apparent cohesion and friction angle, were
established with the cone resistance and degree of saturation. Slight modification was
proposed in evaluating the apparent cohesion with respect to the different fine content in
the soils. As a whole, the proposed method can be successfully applied to individual slopes
to determine the profile thickness and to evaluate the shear strength parameters spatially.
Based on this, hazard assessment of individual slopes can be made.
Analytical solution for Transient MHD flow through a Darcian porous regime in...inventionjournals
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.
Soret Effect And Effect Of Radiation On Transient Mhd Free Convective Flow Ov...inventionjournals
The present paper is concerned to analyze the radiation, Magneto hydrodynamic and soret effects on unsteady flow heat and mass transfer characteristics in a viscous, incompressible and electrically conduction fluid over a semi-infinite vertical porous plate through porous media the porous plate is subjected to a transverse variable suction velocity. The transient, non linear and coupled dimensionless governing equations for this investigation are solved analytically using perturbation technique about a small parameter . the effects of governing parameters on the flow variables are discussed graphically.
Effect of rotation on the onset of Rayleigh-Bénard convection in a layer of F...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
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.
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.
Effect of free surface wave on free vibration of a floating platformeSAT Journals
Abstract Use of floating structures is very common and widespread. Starting from boats, ships and submarines they are used these days for various purposes like platforms for industrial use like offshore oil exploration, civic amenities like floating air strips, defense bases and in some island nations for recreation and habitation. Hence, strength and stability of these platforms are very important. In the present study, the fluid-structure interaction effect on the free vibration frequency of a floating platform is investigated. The fluid is treated as inviscid, incompressible and having a small amplitude irrotational motion. The platform is considered to be of rectangular in size and is made of homogeneous material following Hooke’s law. Finite element technique is adopted for the solution of this problem with eight noded brick elements for the fluid and four noded quadrilateral elements for the plate. The interaction problem of the platform and the fluid is solved independently for the platform and the fluid domain by transferring the pressure to the platform from the fluid and the acceleration of the platform to the fluid sequentially. The effects of the surface wave, thickness and aspect ratio of the platform on free vibration frequencies are studied. It is observed that surface wave reduces the free vibration frequencies significantly for frequencies those are due to the bulging modes of the platform. Key words: - Inviscid, Irrotational, Hydro elasticity, Eigen frequencies, Eigen value.
A New geotechnical method for natural slope exploration and analysisRasika Athapaththu
Geotechnical investigation of natural slopes is challengeable especially when
natural slopes having higher gradients and access is difficult. Also, it is even more prob-
lematic to find the shear strength parameters spatially to evaluate the stability of slopes as
most of the methods available to find the shear strength parameters in the literature are
uneconomical or such methods cannot be applied in vegetated slopes. Recently, authors
have conducted a series of in situ investigations based on the newly developed lightweight
dynamic cone penetrometer to examine its applicability in analyzing the slopes covered
with weathering remnants of decomposed granite. Six patterns were identified based on the
penetration resistance varies with the depth. Spatial variability analysis conducted on
different grid spaces showed that the coefficient of variation of cone resistance varies from
0 to 35 %. Semi-variogram analysis showed that the Spherical Models can be used to
evaluate the spatial variability of weathering remnants of decomposed granite. A series of
laboratory calibration tests based on the lightweight dynamic cone penetration tests and
direct shear tests with pore pressure measurements were conducted at different void ratios
and degrees of saturation. Based on the laboratory calibration test results, a method to
determine the void ratio, e, from the data of qd was presented. Based on this, two formulas
to evaluate the shear strength parameters, apparent cohesion and friction angle, were
established with the cone resistance and degree of saturation. Slight modification was
proposed in evaluating the apparent cohesion with respect to the different fine content in
the soils. As a whole, the proposed method can be successfully applied to individual slopes
to determine the profile thickness and to evaluate the shear strength parameters spatially.
Based on this, hazard assessment of individual slopes can be made.
Analytical solution for Transient MHD flow through a Darcian porous regime in...inventionjournals
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.
Soret Effect And Effect Of Radiation On Transient Mhd Free Convective Flow Ov...inventionjournals
The present paper is concerned to analyze the radiation, Magneto hydrodynamic and soret effects on unsteady flow heat and mass transfer characteristics in a viscous, incompressible and electrically conduction fluid over a semi-infinite vertical porous plate through porous media the porous plate is subjected to a transverse variable suction velocity. The transient, non linear and coupled dimensionless governing equations for this investigation are solved analytically using perturbation technique about a small parameter . the effects of governing parameters on the flow variables are discussed graphically.
Effect of rotation on the onset of Rayleigh-Bénard convection in a layer of F...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
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.
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.
Effect of free surface wave on free vibration of a floating platformeSAT Journals
Abstract Use of floating structures is very common and widespread. Starting from boats, ships and submarines they are used these days for various purposes like platforms for industrial use like offshore oil exploration, civic amenities like floating air strips, defense bases and in some island nations for recreation and habitation. Hence, strength and stability of these platforms are very important. In the present study, the fluid-structure interaction effect on the free vibration frequency of a floating platform is investigated. The fluid is treated as inviscid, incompressible and having a small amplitude irrotational motion. The platform is considered to be of rectangular in size and is made of homogeneous material following Hooke’s law. Finite element technique is adopted for the solution of this problem with eight noded brick elements for the fluid and four noded quadrilateral elements for the plate. The interaction problem of the platform and the fluid is solved independently for the platform and the fluid domain by transferring the pressure to the platform from the fluid and the acceleration of the platform to the fluid sequentially. The effects of the surface wave, thickness and aspect ratio of the platform on free vibration frequencies are studied. It is observed that surface wave reduces the free vibration frequencies significantly for frequencies those are due to the bulging modes of the platform. Key words: - Inviscid, Irrotational, Hydro elasticity, Eigen frequencies, Eigen value.
Research Inventy : International Journal of Engineering and Scienceinventy
esearch Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
DETERMINATION OF IMPACT FORCE ON A NON-SPINNING SPHERE DURING WATER ENTRYAM Publications
This paper extends the study to determine the Impact forces for generalized Oblique water entry. The forces of impact for various cases along with their trajectories are exhibited in the results. All the cases considered are of super cavitating flow conditions. The detailed formulation of how the results are obtained is also discussed with appropriate assumptions and justifications.
Heat Transfer on Steady MHD rotating flow through porous medium in a parallel...IJERA Editor
We discussed the combined effects of radiative heat transfer and a transverse magnetic field on steady rotating flow of an electrically conducting optically thin fluid through a porous medium in a parallel plate channel and non-uniform temperatures at the walls. The analytical solutions are obtained from coupled nonlinear partial differential equations for the problem. The computational results are discussed quantitatively with the aid of the dimensionless parameters entering in the solution.
FIELD AND THEORETICAL ANALYSIS OF ACCELERATED SETTLEMENT USING VERTICAL DRAINS ijiert bestjournal
Mumbai is the region consisting of soft compressibl e marine clay deposits. There are several construction problems on such soils and thu s ground improvement need to be carried out. Vertical drains is generally preferred technique as accelerated settlement is achieved during the construction phase itself. The concept of vertical drains is based on three dimensional consolidation as described by Ter zaghi (1943). Based on this concept,a settlement programme is being developed and an at tempt is made to determine the field to laboratory coefficient of vertical consoli dation ratio by methods proposed by Taylor and Asaoka (1978) for this region by conside ring the case studies namely 1.) Mulund Airoli Bridge approach embankment 2.) Palm B each Marg. Based on this ratio,the rate of consolidation and time required for con solidation in the field can be determined knowing the consolidation parameters.
Effects of Variable Viscosity and Thermal Conductivity on MHD free Convection...theijes
A steady two-dimensional MHD free convection and mass transfer flow past an inclined vertical surface in the presence of heat generation and a porous medium have been studied numerically when the fluid viscosity and thermal conductivity are assumed to be vary as inverse linear function of temperature. The governing partial differential equations are reduced to a system of ordinary differential equations by introducing similarity transformations. The non-linear similarity equations are solved numerically by applying the Runge-Kutta method of fourth order with shooting technique. The numerical results are presented graphically to illustrate influence of different values of the parameters on the velocity, temperature and concentration profiles. Skin friction, Nusselt number and Sherwood number are also completed and presented in tabular form.
Finite element analysis of a floating rectangular plateeSAT Journals
Abstract The free vibration characteristics of a floating rectangular plate considering the fluid-structure interaction effects between the plate and the reservoir are studied. The fluid is assumed to be inviscid, incompressible and the reservoir bottom is assumed to be horizontal and rigid. Finite element technique is used to solve this interaction problem. The eigen frequencies of the plate are computed and the effects of the flexibility of the plate, depth of the reservoir are investigated. Keywords -inviscid,irrotational,eigenfrequency,FEM,VLFS, hydroelasticity.
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
MAGNETOSTATIC SURFACE WAVES IN A LEFT HANDED / FERRITE/ METAL-STRIP-GRATING S...ijrap
The dispersion characteristics for magnetostatic surface waves in a left handed ( LHM)/ferrite/ metal-stripgrating
structure have been investigated. We found that, the waveguide supports backward TE waves
since both permittivity and magnetic permeability of LHM are negative. We also illustrated the
dependence of wave frequency on the reduced wave number for a grating shielding parameter, g values
restricted by the range 0 ≤ g ≥ 1. It is shown that the grating shielding parameter, g induces
magnetostatic backward shorter waves . The leakage through the grating increases with the wave number. The shorter backward magnetostatic waves are guided by the thicker waveguide where the best confinement is achieved
Mindfulness for work life balance is one of the keys to living a healthy and happy life. Balance is something that is innate it all living beings. This presentation discusses ways how balance is a natural process and shares different techniques to empower today's busy professional to own their sense of balance in their work and life.
Satisfy Tattoo Removal Treatment by Laserbellalaserbella
If you want tattoo removed then you need a solution that could ensure you maximum satisfaction. Let's opt for laser tattoo removal treatment to erase your unwanted tattoo.
Research Inventy : International Journal of Engineering and Scienceinventy
esearch Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
DETERMINATION OF IMPACT FORCE ON A NON-SPINNING SPHERE DURING WATER ENTRYAM Publications
This paper extends the study to determine the Impact forces for generalized Oblique water entry. The forces of impact for various cases along with their trajectories are exhibited in the results. All the cases considered are of super cavitating flow conditions. The detailed formulation of how the results are obtained is also discussed with appropriate assumptions and justifications.
Heat Transfer on Steady MHD rotating flow through porous medium in a parallel...IJERA Editor
We discussed the combined effects of radiative heat transfer and a transverse magnetic field on steady rotating flow of an electrically conducting optically thin fluid through a porous medium in a parallel plate channel and non-uniform temperatures at the walls. The analytical solutions are obtained from coupled nonlinear partial differential equations for the problem. The computational results are discussed quantitatively with the aid of the dimensionless parameters entering in the solution.
FIELD AND THEORETICAL ANALYSIS OF ACCELERATED SETTLEMENT USING VERTICAL DRAINS ijiert bestjournal
Mumbai is the region consisting of soft compressibl e marine clay deposits. There are several construction problems on such soils and thu s ground improvement need to be carried out. Vertical drains is generally preferred technique as accelerated settlement is achieved during the construction phase itself. The concept of vertical drains is based on three dimensional consolidation as described by Ter zaghi (1943). Based on this concept,a settlement programme is being developed and an at tempt is made to determine the field to laboratory coefficient of vertical consoli dation ratio by methods proposed by Taylor and Asaoka (1978) for this region by conside ring the case studies namely 1.) Mulund Airoli Bridge approach embankment 2.) Palm B each Marg. Based on this ratio,the rate of consolidation and time required for con solidation in the field can be determined knowing the consolidation parameters.
Effects of Variable Viscosity and Thermal Conductivity on MHD free Convection...theijes
A steady two-dimensional MHD free convection and mass transfer flow past an inclined vertical surface in the presence of heat generation and a porous medium have been studied numerically when the fluid viscosity and thermal conductivity are assumed to be vary as inverse linear function of temperature. The governing partial differential equations are reduced to a system of ordinary differential equations by introducing similarity transformations. The non-linear similarity equations are solved numerically by applying the Runge-Kutta method of fourth order with shooting technique. The numerical results are presented graphically to illustrate influence of different values of the parameters on the velocity, temperature and concentration profiles. Skin friction, Nusselt number and Sherwood number are also completed and presented in tabular form.
Finite element analysis of a floating rectangular plateeSAT Journals
Abstract The free vibration characteristics of a floating rectangular plate considering the fluid-structure interaction effects between the plate and the reservoir are studied. The fluid is assumed to be inviscid, incompressible and the reservoir bottom is assumed to be horizontal and rigid. Finite element technique is used to solve this interaction problem. The eigen frequencies of the plate are computed and the effects of the flexibility of the plate, depth of the reservoir are investigated. Keywords -inviscid,irrotational,eigenfrequency,FEM,VLFS, hydroelasticity.
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
MAGNETOSTATIC SURFACE WAVES IN A LEFT HANDED / FERRITE/ METAL-STRIP-GRATING S...ijrap
The dispersion characteristics for magnetostatic surface waves in a left handed ( LHM)/ferrite/ metal-stripgrating
structure have been investigated. We found that, the waveguide supports backward TE waves
since both permittivity and magnetic permeability of LHM are negative. We also illustrated the
dependence of wave frequency on the reduced wave number for a grating shielding parameter, g values
restricted by the range 0 ≤ g ≥ 1. It is shown that the grating shielding parameter, g induces
magnetostatic backward shorter waves . The leakage through the grating increases with the wave number. The shorter backward magnetostatic waves are guided by the thicker waveguide where the best confinement is achieved
Mindfulness for work life balance is one of the keys to living a healthy and happy life. Balance is something that is innate it all living beings. This presentation discusses ways how balance is a natural process and shares different techniques to empower today's busy professional to own their sense of balance in their work and life.
Satisfy Tattoo Removal Treatment by Laserbellalaserbella
If you want tattoo removed then you need a solution that could ensure you maximum satisfaction. Let's opt for laser tattoo removal treatment to erase your unwanted tattoo.
Offshore structures are continuously exposed to extremely varying aerodynamic
and hydrodynamic loads. The storm waves and breaking waves may cause significant
impact on coastal and offshore structures such as vertical sea wall, wind turbines,
LNG carriers and submarine pipelines etc. The prediction of the breaking wave
impact pressure is the important aspect in the design of those structures. The breaking
wave forces produce the highest hydrodynamic loads on substructures in shallow
water, predominantly plunging breaking waves. Owing to the complex and transient
nature of the impact forces it requires more details concerning the physics of breaking
waves and nature of wave interaction with those structures.
In this paper, A Piston-type wave generator was incorporated in the
computational domain to generate waves. Flow 3D was used for simulating 3D
numerical wave tank. The desired breaking waves are simulated using the concept of
wave focusing using Flow 3D solver. These waves are made to impinge on the elastic
circular cylinders of different materials such as PVC, timber and concrete by varying
the support conditions such as cantilever, both ends fixed, inclined support with 30º
inclination. The hydrodynamic response and the structural response are analysed and
validated with the experimental literatures. The maximum impact pressure transpired
on the cylinder due to plunging wave impact from numerical simulation is found to be
eight times of the non-breaking waves
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
Evaluation of fracture toughness of sintered silica nickel nanocompositeseSAT Journals
Abstract
The micro-Vickers indentation technique is limited to a small area of the specimen surface. It provides a sort of local fracture toughness value, limited to a small portion of the material. But, due to the simplicity of the micro- Vickers indentation test, there has been a steadily increasing interest in its applications. It has been established that classifying on the indentation load, two different types of cracks may form in the Vickers indentation. One type is the Palmqvist crack, while the other is the median type crack which forms in a half penny shape. A Niihara approach is chosen to assess the fracture toughness of silica-nickel Nanocomposites for both type of cracks found in this experiment. The important observation is that with the increase in the amount of nickel, the indentation fracture toughness is found to increased.
Keywords: Micro-Vickers indentation, fracture toughness, Palmqvist crack, Median crack, Nickel, Niihara, Nanocomposites.
Safety Margin of Slope Stability Using Common Deterministic MethodsIJMER
The objective of this research was to develop a model for deterministic slope stability analysis.
The study was performed through different methods of analysis and compared with Bishop simplified
method, the variation of each input parameter ranged using traditional behavior equations to produce a
distribution of the factor of safety verses the variables. A sensitivity analysis is then applied to the output
factor of safety with each variable to select the slope design parameters with acceptable effect on factor
of safety. To demonstrate the application of the deterministic methods developed during this paper, the
methodology was applied to case study to present the effect of each variable on factor of safety, the
study of slope failure was assumed to be circular slip surface .
TRANSMISSION COEFFICIENT (KT) AND REFLECTION COEFFICIENT (KR) ON BREAKWATER T...AM Publications
The results showed a model five submerged condition with the interval value of (KT) = 0,333-0,366 and (KR) = 0,111-0,213 and (KD) = 0,443-0,556, merged condition with the interval value of (KT) = 0,083-0,220 and (KR) 0,171-0,333 and (KD) 0,500-0,671 with a wide of the top breakwater 10 cm.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
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A new geotechnical method for natural slope exploration and analysis
1. 1 23
Natural Hazards
Journal of the International Society
for the Prevention and Mitigation of
Natural Hazards
ISSN 0921-030X
Volume 75
Number 2
Nat Hazards (2015) 75:1327-1348
DOI 10.1007/s11069-014-1384-0
A new geotechnical method for natural
slope exploration and analysis
A. M. R. G. Athapaththu, Takashi
Tsuchida & Seiji Kano
2. 1 23
Your article is published under the Creative
Commons Attribution license which allows
users to read, copy, distribute and make
derivative works, as long as the author of
the original work is cited. You may self-
archive this article on your own website, an
institutional repository or funder’s repository
and make it publicly available immediately.
3. ORIGINAL PAPER
A new geotechnical method for natural slope exploration
and analysis
A. M. R. G. Athapaththu • Takashi Tsuchida • Seiji Kano
Received: 4 March 2014 / Accepted: 9 August 2014 / Published online: 5 September 2014
Ó The Author(s) 2014. This article is published with open access at Springerlink.com
Abstract Geotechnical investigation of natural slopes is challengeable especially when
natural slopes having higher gradients and access is difficult. Also, it is even more prob-
lematic to find the shear strength parameters spatially to evaluate the stability of slopes as
most of the methods available to find the shear strength parameters in the literature are
uneconomical or such methods cannot be applied in vegetated slopes. Recently, authors
have conducted a series of in situ investigations based on the newly developed lightweight
dynamic cone penetrometer to examine its applicability in analyzing the slopes covered
with weathering remnants of decomposed granite. Six patterns were identified based on the
penetration resistance varies with the depth. Spatial variability analysis conducted on
different grid spaces showed that the coefficient of variation of cone resistance varies from
0 to 35 %. Semi-variogram analysis showed that the Spherical Models can be used to
evaluate the spatial variability of weathering remnants of decomposed granite. A series of
laboratory calibration tests based on the lightweight dynamic cone penetration tests and
direct shear tests with pore pressure measurements were conducted at different void ratios
and degrees of saturation. Based on the laboratory calibration test results, a method to
determine the void ratio, e, from the data of qd was presented. Based on this, two formulas
to evaluate the shear strength parameters, apparent cohesion and friction angle, were
established with the cone resistance and degree of saturation. Slight modification was
proposed in evaluating the apparent cohesion with respect to the different fine content in
the soils. As a whole, the proposed method can be successfully applied to individual slopes
to determine the profile thickness and to evaluate the shear strength parameters spatially.
Based on this, hazard assessment of individual slopes can be made.
A. M. R. G. Athapaththu (&) Á T. Tsuchida
Department of Civil and Environmental Engineering, Institute of Engineering, Hiroshima University,
1-4-1, Kagamiyama, Higashi-Hiroshima 739-8527, Japan
e-mail: rasika@hiroshima-u.ac.jp
S. Kano
Kure National College of Technology, 2-2-11, Agaminami, Kure 737-8506, Japan
123
Nat Hazards (2015) 75:1327–1348
DOI 10.1007/s11069-014-1384-0
4. Keywords Site investigation Á Cone resistance Á Spatial variability Á Apparent cohesion Á
Friction angle
1 Introduction
Geotechnical exploration of mountainous slopes is required when the built environment
extends to the foot or into the mountainous areas to safeguard the community and the
properties due to possible landslides or slope failures. The extension of built environment
into the mountainous regions is often seen in many parts of the world, where the most of
the topography is dominated by hills and mountains, with the development of industries
and growing population. Topographically, about 75 % of the total land area of Japan is
hilly and mountainous (Statistical handbook of Japan 2013, Ministry of Internal Affairs
and Communications). Shallow slope failures, induced by torrential rainfall in rainy sea-
sons or accompanied by typhoons, are common in the western part of Japan, especially in
Hiroshima, Yamaguchi, and Shimane prefectures (e.g., Chigira et al. 2011; Wang et al.
2003; Futagami et al. 2010; Nakai et al. 2006; Dissanayake 2002; Sasaki et al. 2001).
Hiroshima Prefecture possesses 31,987 hazardous areas susceptible to landslide disasters,
the largest number of such areas in any prefecture in Japan (Hiroshima Prefecture, 2011).
About 75 % of the lands (8,477 km2
) in the prefecture are hilly and mountainous and are
covered with weathering remnants of decomposed granite, locally called ‘Masado.’ From
the geotechnical point of view, the failures are mainly due to the rise of ground water table
and the loss of in situ shear strength of soils.
Hiroshima prefectural government has developed a hazard assessment system based on
the measured rainfall and the rainfall—failure relationship in each 5 km 9 5 km area
obtained from the past records of the failures (Hiroshima Prefectural government, 2006). In
this system, the caution for the slope failures or the evacuation order can be stated to an
area of 5 km 9 5 km, and the hazard of an individual slope cannot be made. Also, the
present risk assessment method is an empirical and is not a theoretical or geotechnical basis
approach. For sound analysis of slope stability problems, gradient of the slope, in situ shear
strength parameters, and the change of the strength due to the dissipation of suction and the
rise of ground water table under heavy rainfall conditions need to be taken into consid-
eration. Exploration of slopes in the region poses immense challenge to the engineers and
researchers due to the difficulty in determining the thickness of soil profile and shear
strength parameters spatially. Determination of shear strength parameters based on tradi-
tional laboratory testing methods are expensive, time-consuming, and sometimes com-
plicated and require extreme care in sampling. Also, presently available in situ tests such as
SPT and CPT are very expensive, time-consuming and cannot be instrumented in areas
where access is difficult, whereas the results obtained from other methods (vane shear etc.)
are not sufficiently reliable for geotechnical analyses.
Therefore, a new field test technique is required to assess the natural slopes having
dense vegetation to overcome the shortcomings of the existing methods. The charac-
teristics of the proposing technique have to be lightweight, economical, safe, and reli-
able. With this aim, the academics and the researchers in geotechnical laboratory of
Hiroshima University, Japan, have experimented a new field method based on dynamic
cone penetrometers: recently introduced lightweight dynamic cone penetrometer and
widely used portable dynamic cone penetrometer. Based on the series of investigations
1328 Nat Hazards (2015) 75:1327–1348
123
5. and laboratory experiments, a new methodology is presented. A method to evaluate shear
strength parameters of weathering remnants of decomposed granite slopes susceptible to
failure in Hiroshima Prefecture is presented based on the data of cone penetration
resistance. This research may provide promising of applications to the 31,987 natural
slopes which identified as hazardous zones and to develop new hazard system for
evacuation purposes.
Cone penetration tests are popular field applications in geotechnical explorations. Each
method differs from other in terms of operation and applicability. In this study, lightweight
dynamic cone penetrometer and portable dynamic cone penetrometer were applied in the
natural slopes. Lightweight dynamic cone penetration test (LWDCPT) has been designed
and developed in France since 1991(Ito et al. 2006; Langton 1999). The schematic view of
LWDCPT device is shown in Fig. 1a. The total weight of all parts including the carrying
case of the device is 20 kg. It mainly consists of an anvil with a strain gauge bridge, central
acquisition unit (CAU), and a dialog terminal (DT). The hammer is a non-rebound type and
weighs 1.73 kg. The stainless steel rods are 14 mm in diameter and 0.5 m in length. Cones
having horizontal sectional area 2, 4, and 10 cm2
are available, and a cone holder is used to
fix the 4 or 10 cm2
cones to the rod. Figure 1c shows a sketch of cone and cone holder. The
device can be operated by one person at almost any location to a depth of 6 m (Langton
1999).
The blow from the hammer to the anvil provides energy input, and a unique micro-
processor records the speed of the hammer and depth of penetration. The dynamic cone
resistance (qd) is calculated from the modified form of Dutch Formula (Cassan 1988;
Chaigneau et al. 2000) as shown in Eq. (1). It should be noted that the expression for
energy used in this formula (‘MV2
) is for kinetic energy, as the energy input is variable
and is delivered manually by the blow of the hammer. On the screen, dialog terminal
displays not only real-time data both graphically and in tabular form but also dynamic cone
resistance and penetration depth.
qd ¼
1
A
:
1=2 MV2
1 þ P
M
:
1
x90
ð1Þ
where x90 = penetration due to one blow of the hammer by 90° cone (m), A = horizontal
sectional area of the cone (m2
), M = weight of the striking mass (kg), P = weight of the
struck mass (kg) and V = speed of the impact of the hammer (m/s).
Portable dynamic cone penetration test (PDCPT) is commonly known as ‘simple
penetration test’ and widely used in Japan as a practical substitution for standard pen-
etration test (SPT). The configuration diagram of PDCPT is shown in Fig. 1b. Due to the
portability of the apparatus, it has been widely used in many geotechnical engineering
applications in the recent past. This consists of a guide rod, a series of rods, hammer, and
a cone. The upper part of the guide rod is 35 cm in length. All other rods are 50 cm in
length and 16 mm in diameter. Cone, which is 60°, is 25 mm in diameter. Hammer,
which weighs 5 kg, is dropped along the guide rod from 50 cm above the knocking head
called a ‘blow.’ The number of blows (N) and driven depth (d) is recorded usually at 10-
cm penetration intervals. The number of blows required for the 10-cm penetration is
referred as Nd. If this condition is not met, Nd is calculated using Eq. (2) (Japanese
standards and explanations of geotechnical and geoenvironmental investigation methods
2013).
Nd ¼ 10
N
d
ð2Þ
Nat Hazards (2015) 75:1327–1348 1329
123
6. 2 Site investigation and analysis of field data
The major part of the investigation was carried out using the newly developed LWDCPT at
Ikeno-ue situated on the northern slope of Mt. Gagara (Fig. 2) located about 800 m east of
the academic area of Hiroshima university, Japan. An area of 20 m 9 50 m was selected
between the ridge and the middle slope and divided the area into 5 m 9 5 m grids as
shown in Fig. 3. LWDCPTs were conducted at each of 55 grid nodes. At each node, three
tests were conducted until the cone resistance becomes to 10 MPa, which is good enough
to determine the hard stratum of the soil profile. In addition, PDCPTs were conducted to
compare the operational performance and to develop a relationship with LWDCPT at
selected grid points at the same site. Later, to examine the spatial variability of cone
resistance varies with space, a series of in situ LWDCPTs were conducted at 2.5, 1, and
0.25 m grid spaces within the main grid. More details on the site investigation were
furnished in the literature published by Athapaththu et al. (2005, 2006a).
2.1 Analysis of the cone resistance data for classification
The data of LWDCPTs collected from 55 nodes of Mt. Gagara were statistically analyzed,
and the average cone resistance in 5-cm intervals was calculated. The penetrograms
(c)
Cone 4, or 10 cm2
Cone Holder
(Striking mass)
(a)
Dialogue
Terminal Rod
Hammer with no rebound
Central Acquisition Unit
Anvil with Strain Gauge
Bridge
Cone
Scale
Rod Guide
(Struck mass)
Hammer
Knocking Head
Guide rod
Upper length: 35 cm
Lower length: 50 cm
Rod
Cone
35 cm
50cm
(b)
Fig. 1 Schematic assemble view of cone penetration test apparatus. a Lightweight dynamic cone
penetrometer, b Portable dynamic cone penetrometer, c cone and cone holder
1330 Nat Hazards (2015) 75:1327–1348
123
7. (soundings) of each location were graphically presented, and further analysis was carried
out to examine the possible similarities within them. Observations were made as the most
of the soundings could be fitted into six patterns based on the trend of variation in cone
resistance with depth.
For the convenience of the future references, the classified patterns were numbered from
‘A’ to ‘F’ and the trend of variation is graphically illustrated in Figs. 4 and 5. The
characteristics of each pattern are summarized in Table 1.
2.2 Classification of soundings according to the patterns
In situ investigations were carried out in different phases on natural slopes and valleys
covered with weathering remnants of decomposed granite at selected locations using
dynamic cone penetrometers by geotechnical teams. The penetrograms obtained in those
locations were classified into the six trend of patterns observed in the base study as
illustrated in Figs. 4 and 5. The LWDCPTs carried out at two locations in Mt. Gagara,
(a) (b)
Yasuura
Mukaihara
Aratani
Miyakegawa
Kure
Mt. Gagara
Miyajima
Asakita
Saeki
Shiwa
Fig. 2 In situ investigation locations. a Some sites at Japan and South Korea, b Sites in Hiroshima
Prefecture
Fig. 3 Grid arrangements with
contours
Nat Hazards (2015) 75:1327–1348 1331
123
8. Hiroshima Prefecture, and two slopes in Mt. Rokko in Kobe as shown in Fig. 2b were
classified. Pattern D dominates in Mt. Gagara and shallow profiles were observed in Mt.
Rokko.
0
1
2
3
4
5
6
0 5 10 15
Depth(m)
Cone resistance, qd (MPa)
c-2
d-2
d-4
d-7
e-1
e-2
e-3
Pattern A
0
1
2
3
4
5
6
0 5 10 15
Depth(m)
Cone resistance, qd (MPa)
d-6
a-3
a-1
b-3
c-1
c-3
c-5
d-1
d-3
d-5
c-6
Pattern B
0
1
2
3
4
5
6
0 5 10 15
Depth(m)
Cone resistance, qd (MPa)
a-11 b-5
b-6 b-7
b-8 b-11
c-7 c-8
Pattern C
0
1
2
3
4
5
6
0 5 10 15
Depth(m)
Cone resistance, qd (MPa)
a-6
c-10
c-11
d-11
a-5 Pattern D
0
1
2
3
4
5
6
0 5 10 15
Depth(m)
Cone resistanc, qd (MPa)
c-9
d-8
d-9
d-10
b-10
Pattern E
0
1
2
3
4
5
6
0 5 10 15
Depth(m)
Cone resistance, qd (MPa)
a-8
b-9
e-9 Pattern F
Fig. 4 Categorizations of soundings—six patterns
0
1
2
3
4
5
6
0 5 10 15
Depth(m)
Penetration resistance , qd (MPa)
Pattern C
Pattern B
Pattern A
0
1
2
3
4
5
6
0 5 10 15
Depth(m)
Penetration resistance , qd (MPa)
Pattern F
Pattern D
Pattern E
Fig. 5 The average trend of the six patterns for weathering remnants of decomposed granite
1332 Nat Hazards (2015) 75:1327–1348
123
9. The PDCPT data were collected from two site locations from district of Asakita, three
locations from districts of Saeki and Miyajima, and four locations from district of Kure in
Hiroshima Prefecture. The locations in each district are shown in Fig. 2b. Geologically, all
these areas are covered with weathering remnant of decomposed granite. The PDCPT data
collected from 54, 59, 63, and 94 in situ test locations of Miyajima, Saeki, Asakita, and
Kure districts, respectively, were reanalyzed based on Eq. (3) that was developed based on
the Mt. Gagara data. The equation is shown later in this paper. The calculated qd-depth
relationship of each sounding was compared with the six patterns identified at Mt. Gagara,
and the results are shown in Fig. 6. It was observed that the most of the soundings could be
fitted into one of the six patterns. Most of the in situ test locations of Kure and Asakita
showed comparatively shallow soil profiles (2.0 m), and hence, majority of soundings
were identified as patterns C, D, E, and F. Penetrograms fitted to patterns A and B of those
locations were less than 15 %. Saeki and Miyajima showed significantly higher percentage
of soundings identified as patterns A and B than Kure and Asakita. However, most of the
penetrograms in Saeki and Miyajima, which showed shallow profiles, were identified as
patterns D, E, and F. This analysis revealed that the in situ shear strength–depth rela-
tionship of most of the profiles can be classified to one of the six patterns established, to a
reasonable accuracy.
The in situ investigation was carried out at southern part of South Korea with the aid of
LWDCPT recently. The areas Namwon, Chamgpyuon, and Taegok are covered with
weathering remnants of decomposed granite. Part of the slope at Numwon was undergone a
local landslide failure, and other two sites are identified as slopes susceptible to failures.
Figure 7 shows the classification of sounding collected from South Korea based on the
classification developed for Mr. Gagara. It was seen that the all sounding can be fitted into
one of the six patterns. Moreover, major portion of the soundings at Namwon was iden-
tified as patterns D and E.
Some of the data collected from the area of Shiwa, in Hiroshima Prefecture, Japan,
showed combination of patterns. This site has undergone a retaining wall failure a few
years ago, and LWDCPTs were conducted on the site recently. Figure 8 demonstrates
some of the soundings of the site. It can be seen that same location has more than one
pattern.
Table 1 Characteristics of the patterns (modified after Athapaththu et al. 2006a, b)
Pattern Characteristics
A A gradual increase of penetration resistance with depth. These profiles show a comparatively thick
weathering front over the bed rock
B Gradual increase of penetration resistance with depth. However, penetration resistance is higher
than that of pattern A. This group also shows thick weathering front
C This class shows considerably shallow profiles than those of patterns A and B. Gradual increase of
cone resistance with the depth with greater increment ratio
D Although the profile thickness is similar to that of pattern C, the trend of increases in the cone
resistance with depth is quite low, showing very low values of penetration resistance, about
1 MPa, almost up to 2.0 m. This soil is mostly the colluvium
E The trend of increase in cone resistance is similar to that of pattern D. However, the profile
thickness is less: about 1.2 m
F This group shows the shallowest profiles (total depth is about 0.5 m) and exhibits increment ratio
of higher penetration resistance
Nat Hazards (2015) 75:1327–1348 1333
123
10. Pattern A
39%
Pattern B
13%
Pattern D
48%
Mt. Gagara-Slope 1
Pattern B
14%
Pattern D
50%
Pattern E
29%
Pattern F
07%
Mt. Gagara-Slope 2
Pattern A
25%
Pattern D
38%
Pattern E
25%
Pattern F
12%
Mt. Rokko, Kobe-Slope 1
Pattern A
20%
Pattern B
05%
Pattern C
05%
Pattern D
21%
Pattern E
24%
Pattern F
25%
Mt. Rokko, Kobe-Slope 2
Pattern A
3.2%
Pattern B
5.3%
Pattern C
25.5%
Pattern D
9.6%
Pattern E
42.6%
Pattern F
9.6%
None
4%
Kure
Pattern A
13.8%
Pattern B
13.8%
Pattern C
5.2%
Pattern D
25.9%
Pattern E
17.2%
Pattern F
24.1%
Saeki
Pattern A
3.7%
Pattern B
16.7%
Pattern C
11.1%
Pattern D
27.8%
Pattern E
14.8%
Pattern F
24.1%
None
1.8%
Miyajima
Pattern A
7.9%
Pattern B
6.3%
Pattern C
27%
Pattern D
6.4%
Pattern E
31.7%
Pattern F
15.9%
None
4.8%
Asakita
Fig. 6 Classification of soundings according to the patterns (Japan)
Pattern B
6.7%
Pattern D
33.3%
Pattern E
33.3%
Pattern F
26.7%
Namwon-site 1
Pattern A
30%
Pattern B
20%
Pattern C
20%
Pattern E
20%
Pattern F
10%
Namwon-site2 (Daegok)
Pattern C
50.0%
Pattern D
16.7%
Pattern E
16.7%
Pattern F
16.6%
Dam yang
Fig. 7 Grouping of South Korean soundings to the established patterns
0
0.5
1
1.5
2
2.5
3
0 2 4 6 8 10
Depth(m)
Penetration resistance, qd (MPa)
7.5 m from retainig wall
Bed rock
Collapsed soil
(shows Pattern D)
insitu weatherd soil
(shows Pattern C)
0
0.5
1
1.5
2
2.5
3
0 2 4 6 8 10
Depth(m)
Penetration resistance, qd (MPa)
35m from retainig wall
Bed rock
Soil from collapsed
embankment
(shows Pattern D)
0
0.5
1
1.5
2
2.5
3
0 2 4 6 8 10
Depth(m)
Penetration resistance, qd (MPa)
50 m from retainig wall
Bed rock
Soil from collapsed
embankment
(shows Pattern D)
Fig. 8 Soundings show different patterns at a same location
1334 Nat Hazards (2015) 75:1327–1348
123
11. 2.3 Comparison of the operational performance of LWDCPT and PDCPT
The applicability of LWDCPT and PDCPT for the investigation of natural slopes and
valleys and operational performances of both are discussed in this section. Both LWDCPT
and PDCPT devices reduce cost and time in completing a typical site characterization
activity. In addition to those facts, both can be instrumented in adverse topographical
conditions (e.g., gradient more than 30° and highly vegetated slopes) and the disturbance to
the environment is comparatively low. However, LWDCPT has following advantages over
PDCPT.
1. Number of persons required to perform the LWDCPT is less than that of PDCPT. One
person can handle the device at almost any location. At least 2 persons are required to
carry out PDCPT.
2. LWDCPT displays the real-time data while in operation on the dialog terminal. This
facility provides image to the investigator about subsurface material conditions and to
decide the additional tests required at the site itself.
3. The least count of recording the data is 0.01 MPa. However, up to .001 MPa displays
in the screen. This is good enough for determination of cone resistance in weak soils.
Unlike in other in situ tests, LWDCPT provides more reliable measurements even at
thin weak layers due to continuous recording of data to a greater accuracy.
4. The human errors can be avoided using LWDCPT as it operates in variable energy
input given by the hammer and data record automatically.
5. Due to the availability of ‘hand protection’ as equipped with the Anvil, the possibility
of an injury by the hammer is very low.
6. The efficiency of completing a typical site characterization by LWDCPT is longer than
that of PDCPT. This is graphically shown in Fig. 9. It was found that LWDCPT is
about 200 % faster than PDCPT in carrying out a test at the field. However, due to
terrain difficulties, time taken to perform the tests for 1 m in Kobe is higher than in Mt.
Gagara.
2.4 Correlations of cone resistance
The data collected from different sites were used for the development of correlations
between the cone resistances. Athapaththu et al. (2007b) statistically analyzed the
LWDCPT (qd) and PDCPT (Nd) data collected from Mt. Gagara and developed a corre-
lation between qd and Nd for weathering remnants of decomposed granite as shown in
Fig. 10a and Eq. (3). Here, Nd is number of blow counts for 10-cm penetration and qd is in
MPa. As far as authors aware of, there are no records available in the literature in cor-
relating qd with Nd for weathering remnants of decomposed granite. To develop a rela-
tionship between SPT N value and Nd, data collected from Asakita, Saeki, Miyajima, and
Kure were used. A fairly good linear relationship was established between Nd and SPT N
value by Athapaththu et al. (2007b) for the weathering remnants of decomposed granite
and is shown in Fig. 10b and Eq. (4). Based on the above relationships, a cross-relationship
between SPT N value and qd was developed and is shown in Eq. (5).
qd ¼ 1=2N
3=4
d ð3Þ
Nd ¼ 2:2N ð4Þ
Nat Hazards (2015) 75:1327–1348 1335
123
12. N ¼ 1:15q
4=3
d ð5Þ
2.5 Spatial variability of cone resistance
In general, soils have been formed by combination of various geological, environmental,
and physiochemical processes. The in situ properties of soils vary with both vertically and
horizontally are much important for most of the geotechnical analyses and designs. Several
studies have investigated inherent uncertainty in natural soil properties (e.g., Kulhawy
1992; Lumb 1966; VanMarcke 1977, Vanmarcke 1983; Asaoka and A-Grivas 1982; Spry
et al. 1988; Orchant et al. 1988; Soulie et al. 1990; Chaisson et al. 1995; Phoon and
Kulhawy 1999). Soils derived from weathering remnants of decomposed granite are
inherently heterogeneous. However, a little information is available on the spatial vari-
ability for weathering remnants of decomposed granite found in Japan (e.g., Galer 1999).
Athapaththu et al. (2007b) carried out 2D kriging to analyze LWDCPT data collected at 5-,
0
2
4
6
8
10
12
14
16
18
20
LWDCPT PDCPT
Requiredtimefor1minvestigation
(minutes)
Mt. Gagara, Hiroshima, Ave.Depth=3.0m
Rokko, Hyogo, Ave.Depth=1.7m
0
10
20
30
40
50
60
70
LWDCPT PDCPT
Requiredtimeforthetestatapoint
(minutes)
Mt. Gagara, Hiroshima Ave.Depth=3.0m
Rokko, Hyogo, Ave.Depth=1.7m
(a) (b)
Fig. 9 Time consumption to complete 1 m penetration
qd = ½Nd
¾
0
1
10
0 10 20 30 40 50
qd(MPa)
Nd -PDCPT (blow counts)
Nd = 2.2 N
0
10
20
30
40
50
0 2 4 6 8 10 12 14 16 18 20
Nd-PDCPT(blowcounts)
N-SPT (blow counts)
(a) (b)
Fig. 10 Relationship between cone resistance qd, Nd, and N
1336 Nat Hazards (2015) 75:1327–1348
123
13. 2.5-, 1-, and 0.25-m grid spaces from Mt. Gagara to examine the variability in the space
and also to determine the spacing for in situ tests for future investigations. The scatter of
the cone resistance at different grid spaces was quantitatively analyzed by means of
coefficient of variation (COV). COV measures the degree into which the set of data varies
and often refers as the relative standard deviation. The mathematical formula to find COV
is shown in Eq. (6).
COV ¼
r
X
à 100 % ð6Þ
where r is the standard deviation and X is the mean.
Figure 11a shows the range of COV along the soil profile (i.e., with depth) for
different grid spaces, and Fig. 11b shows the COV varies with different grid spaces for
selected depths, 0.1, 0.5, 1.0, 1.5, 2.0, and 2.5 m. The graphs reveal that the COV varies
from 0 to 35 % for all range of cone resistance data collected at different grid spaces and
depth. The COV of cone resistance can be presented about 20 % throughout the depths
of weathering remnants of decomposed granite profiles at close proximity. This is almost
similar in presenting typical geotechnical engineering parameters. More information
about the analysis can be found from the literature furnished by authors (e.g., Atha-
paththu et al. 2007a).
Geo-statistics, and particularly the semi-variogram, has been shown to be a useful
technique in predicting the data in recent studies, and hence, it has been applied for the
present study. 2D kriging was adopted for the current analysis of cone resistance data.
Semi-variograms for the Spherical and the Power Models were calculated for six different
depths at Z = 0.1, 0.5, 1.0, 1.5, 2.0, and 2.5 m. The depth was measured from the ground
surface, and the assumption was made as the soil profile is parallel to the bed rock.
0
0.5
1
1.5
2
2.5
3
0 10 20 30 40 50 60
Depth(m)
Coefficent of Variation (%)
2.5 m
1.0 m
0.25 m
0
5
10
15
20
25
30
35
40
0 0.5 1 1.5 2 2.5 3
CoefficentofVariation(%)
Grid Distance
(a) (b)
0.1 m 0.5 m
1.0 m 1.5 m
2 m 2.5 m
Fig. 11 COV varies with depth and different grid spaces. a COV varies with depth, b COV varies with grid
spaces
Nat Hazards (2015) 75:1327–1348 1337
123
14. The cone resistance, qd, at an unknown location of interest in XY plane with selected Z
coordinate from the ‘n’ number of data can be written as in Eq. (7) below.
qdðiÃ
Þ ¼
Xn
iÀ1
wi à qdðiÞ ð7Þ
where qd(i*) is the cone resistance at unknown location, qd(i) is the measured cone
resistance at the ith location, wi is an unknown weight for the measured value at the ith
location and the summation of wi must be made equal to one to avoid biasness of the
predictor.
The observed values and the predicted values of cone resistance are made as small as
possible in order to minimize the statistical expectations of the following formula, from
which the parameters of semi-variograms were obtained as shown in Eq. (8).
min
Xn
i¼1
cðhÞijÀmeasured À cðhÞijÀcalculated
h i2
( )
ð8Þ
The measured semi-variance of ith and jth locations, cðh)ij, can be calculated from the
basic formula shown in Eq. (9).
cðh)ij ¼
1
2
ðqi
d À qj
dÞ2
ð9Þ
where qd
i
is the cone resistance at ith location, qd
j
is the cone resistance at jth location.
The solution to the minimization, constrained by un-biasedness, gives the kriging
equations in a following matrix form
c11 Á Á Á c1n 1
..
. ..
. ..
. ..
.
cn1 Á Á Á cnn 1
1 Á Á Á 1 0
0
B
B
B
@
1
C
C
C
A
Â
w1
..
.
wn
m
0
B
B
B
@
1
C
C
C
A
¼
c1p
..
.
cnp
1
0
B
B
B
@
1
C
C
C
A
ð10Þ
where cij denotes the modeled semi-variogram values between all pairs of observed qd
values, cip denotes the modeled semi-variogram values based on the distance between the
ith location and the prediction location, m (in the weight matrix) is an unknown constant,
which arises because of the un-biasedness constraint and can be determined through the
calculation process.
Solving the matrix as shown in Eq. (10), wi can be determined and the solution for
unknown qd at location ‘p’ can be calculated from Eq. 7.
The cone resistance data collected from Mt. Gagara have been analyzed for six depth
intervals (i.e., Z = 0.1, 0.5, 1.0, 1.5, 2.0, and 2.5 m) based on Eqs. (7), (8), (9), and (10).
Figure 12 demonstrates the Spherical and the Power Models calculated for several depth
intervals with their corresponding relationships. The Spherical Model was found to be the
best-fitted semi-variogram for Masado profiles. The Power Model also showed reasonable
agreement with the observed data. Therefore, these models can be applied to evaluate the
cone resistance in an unknown location of interest. The range of influence of Masado soils
was found to be varying with the profile depth. The correlated distance varies from 11 to
30 m with the depth increases from 0.1 to 2.5 m. This gives some idea for determination of
grid spaces in carrying out in situ investigation of natural slopes having weathering
remnants of decomposed granite.
1338 Nat Hazards (2015) 75:1327–1348
123
15. 3 Laboratory experimental setup and analysis
The main objective of this part of research was to establish sound relationship between shear
strengthparameters, /d and c withconeresistance, qd, under different voidratios and degrees of
saturation. To fulfill this task, a series of laboratory direct shear tests was carried out varying
void ratios and degrees of saturation. Also, laboratory scale calibration tests were conducted
based on LWDCPT for different void ratios and degrees of saturation. The methodology, data,
analyses and results of these experiments are discussed in the following sections.
3.1 Direct shear tests on remolded samples
A series of laboratory experiments was carried out to develop relationships between shear
strength parameters with void ratios and degrees of saturation. Soil samples collected at
Fig. 12 Modeled semi-variograms for weathering remnants of decomposed granite profiles
Nat Hazards (2015) 75:1327–1348 1339
123
16. Mt. Gagara were fairly air-dried, and soils passing through 2-mm sieve were used for the
laboratory tests. Reconstituted specimens were prepared for the laboratory direct shear
tests. A sectional view of the direct shear apparatus used in this study is shown in Fig. 13.
Even though undisturbed specimens provide better representation of natural conditions
than reconstituted specimens, it is practically difficult to make undisturbed specimens to a
certain degree of saturation and void ratio. Therefore, reconstituted specimens were pre-
ferred for the laboratory tests to determine shear strength parameters under different void
ratios and degrees of saturation. The testing program consisted of: (i) consolidated drained
direct shear box tests conducted at void ratios ranging from 0.7 to 1.0 in 0.1 increments at a
constant degree of saturation; (ii) repeat (i) at different degrees of saturation varying from
40 to 100 %. Also, tri-axial tests were conducted for different void ratios under 100 %
degree of saturation. Direct shear tests with the measurement of pore pressure were con-
ducted at all cases mentioned above except for the cases at the void ratio of 1.0. A ceramic
disk with an air entry value 200 kPa was sealed on to the bottom half of the shear box. Pore
pressure was measured through the pressure gauge connected to the ceramic disk as shown
in Fig. 13.
The apparent cohesion, cd, and the friction angle, /d, varying with void ratios under
different degrees of saturation are shown in Fig. 14a and b, respectively. /d is in degrees
(°), cd is in kPa, and Sr is in percentage (%). No clear trend was observed in /d with degree
of saturation, and data were scattered within a small range. Therefore, the average line was
drawn to determine /d varies with void ratios as shown in Fig. 14a. Further analyses of the
data revealed that apparent cohesion ‘cd’ can be developed as linear functions of void ratios
for different degrees of saturation. It can be observed that the apparent cohesion decreases
more than 50 % when the degree of saturation varies from 40 to 80 % in all range of void
ratios. The graphical presentation can be deduced to the form of mathematical formula to
express the shear strength parameters. Equation (11) shows the friction angle in terms of
void ratios, while Eq. (12) displays the apparent cohesion in terms of void ratio and degree
of saturation. Therefore, shear strength parameters can be calculated for known void ratio
and degree of saturation for weathering remnants of decomposed granite based on the
developed Eqs. (11) and (12).
/d ¼ 52:7 À 19:2e ð11Þ
cd ¼ 27:5 À 0:146Sr À 14:2e ð12Þ
Fig. 13 Direct shear test
apparatus with pore pressure
measurements
1340 Nat Hazards (2015) 75:1327–1348
123
17. 3.2 Laboratory calibration tests
The main objective of this part of the research was to develop strength correlations
between qd and shear strength parameters, cd and /d, and thereby using the relationship to
predict the shear strength parameters from the in situ LWDCPTs data. A series of
LWDCPT was performed under void ratios ranging from 0.6 to 1.1 and degrees of satu-
ration ranging from 50 to 90 %. Acryl cylinders each 29 cm in diameter and 20 cm in
height were fastened through nuts and bolts, and porous plate was sealed to the bottom
cylinder. The number of acryl cylinders used for each test was varied from two to six, and
some tests were conducted by applying surcharge weights. Two to three trials of
LWDCPTs were performed at each preparation, and specimens were taken at each cylinder
for water content and void ratio measurements in order to compare the values before and
after the tests. The slight variation of degrees of saturation and void ratios were observed
along the soil chamber even though those parameters were fixed to a particular value prior
to each test. However, those variations were considered in analyzing the test data. Com-
paratively, low values of cone resistance were recorded at high degrees of saturation.
Moreover, high void ratios implicate low cone resistance. These are clearly displayed in
the curves drawn in Fig. 15. The graphical relationships shown in Fig. 15 can be
approximated to the formula shown in Eq. (13).
e ¼ 1:19 À 0:084 lnðqd5Þ À 0:0074Sr ð13Þ
where qd5 was determined from the laboratory model tests conducted on surcharge weights.
It is the cone resistance for 5 kPa overburden stress and can be found from Eq. (14). ct is
the overburden stress in kPa, and qd is in MPa.
qd5 ¼ qd À 0:01ðctz À 5Þ ð14Þ
By combining Eqs. (11), (12), and (13) Tsuchida et al. (2011) presented the shear
strength parameters in terms of cone resistance as shown in Eqs. (15) and (16). Note that qd
is in MPa, and Sr is in %. The friction angle /d is in degrees and cohesion (drained) in kPa.
The developed formulas can be used to evaluate the shear strength parameters for a known
degree of saturation.
(a) (b)
Fig. 14 Variation of apparent cohesion and friction angle with void ratios for different degrees of
saturation. a Friction angle, b Apparent cohesion
Nat Hazards (2015) 75:1327–1348 1341
123
18. /d ¼ 29:9 þ 1:61 lnðqd5Þ þ 0:142Sr ð15Þ
cd ¼ 10:6 þ 1:19 lnðqd5Þ À 0:041Sr ð16Þ
3.3 Effect of fine content in determination of shear strength parameters
However, the effect of the fine content in shear strength parameters determined by cone
resistance data has not been considered in above derivations. Therefore, this part of study
was aimed to examine the variation of shear strength parameters, apparent cohesion, cd,
and friction angle, /d, with the different fine contents. Weathering remnants of decom-
posed granite collected from Mt. Gagara, same soil used for the laboratory tests to develop
the relationship of shear strength parameters, sieved through 75-lm sieve. The soil passing
through the sieve was used as the fine fraction. A series of laboratory direct shear tests was
conducted varying fine fraction 0–15 % by weight. The degree of saturation and void ratio
were kept to 40 % and 0.9, respectively, when preparing the remoulded samples. The fine
fraction, void ratio and degree of saturation were determined after the tests even though
those were made constant prior to the tests. Figure 16a and b shows the relationships
between the friction angle and apparent cohesion vary with the fine content, respectively,
obtained from the direct shear tests. Also, shear strength parameters estimated from Eqs.
(11) and (12) were plotted in the same figure to compare variation. As seen in the figure,
the friction angle determined from experiments is slightly greater than estimated values.
The estimated value is 90 % of the experimental value irrespective of fine fraction, and
therefore, estimated value needs to be corrected by multiplying 0.9. However, apparent
cohesion was found to be increased with the fine fraction.
Figure 17a illustrates modification factor, the ratio of experimental value to the esti-
mated value Eqs. (11) and (12) for the apparent cohesion. The modification factor increases
with the fine content. The line was drawn considering the modification factor equal to 1
when there is no fine content in the soil. It can be applied to correct the apparent cohesion
obtained in Eqs. (12) and (16). The apparent cohesion obtained from the experiments and
that estimated from established equations before and after application of modification
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
0.5 0.6 0.7 0.8 0.9 1 1.1 1.2
Penetrationresistance,qd5(MPa)
Void ratio , e
Sr=40%
Sr=50%
Sr=60%
Sr=70%
Sr=80%
Sr=90 100%
Fig. 15 Variation of cone resistance with void ratios under different degrees of saturation
1342 Nat Hazards (2015) 75:1327–1348
123
19. factor is shown in Fig. 17b. In determination of friction angle, a constant factor of 0.9
needs to be applied for the estimated values based on Eqs. (11) and (15).
3.4 Comparison of estimated and experimental shear strength parameters for some
field cases
As a whole, the friction angle can be determined from the proposed Eq. (15) for a known
cone resistance data and known degree of saturation. However, when determining the
apparent cohesion, the value calculated from Eq. (16) needs to be corrected based on
Fig. 17. The proposed method to determine the shear strength parameters was examined
through the triaxial tests conducted on undisturbed samples collected at 30 cm depth near
the locations where LWDCPTs were carried out. The examination was carried out at 4
locations in Hiroshima Prefecture: Miyakegawa, Mukaihara, Yasu-ura, and Aratani val-
leys. The undisturbed samples were carefully trimmed into the triaxial specimen and
compressed after the consolidation under confining stresses of 9.8, 19.6, and 39.2 kPa in
drained conditions. The values of friction angle and the apparent cohesion were calculated
from the data of tri-axial compression tests. The estimated shear strength parameters from
25
30
35
40
45
0 5 10 15 20
Frictionangle,d)(
Fine content Fc (%)
Direct shear test
Estimated
Linear (Direct shear test)
Linear (Estimated)
0
5
10
15
20
0 5 10 15 20
Apparantcohesion,cd(kPa)
Fine content Fc (%)
Direct shear test
Estimated
(a) (b)
Fig. 16 Variation of shear strength parameters with fine fraction based on direct shear test. a Friction angle,
b Apparent cohesion
1.0
1.2
1.4
1.6
1.8
0 5 10 15 20
Modificationfactor
Fine content, Fc (%)
0
5
10
15
20
0 5 10 15 20
Apparentcohesion,cd(kPa)
(Experimental)
Apparent cohesion, cd (kPa)
(Estimated)
Before modified
After modified
(a) (b)
Fig. 17 Modification factor for the apparent cohesion and comparison
Nat Hazards (2015) 75:1327–1348 1343
123
20. the proposed equations based on cone resistance data and that determined through labo-
ratory tests are illustrated in Fig. 18. It can be seen that the friction angle estimated and that
obtained from tri-axil tests are slightly different in all sites. However, experimented and
corrected apparent cohesion was found to be very close in Mukaihara and Yasuura valleys.
More data need to make sound conclusion of the proposed modification factor.
3.5 Application of the findings to geotechnical investigations and discussion
In this study, in situ investigation of natural slopes and shear strength parameters required
for the analysis were thoroughly discussed. Further, shear strength parameters were
evaluated based on the cone resistance data. The proposed method to evaluate shear
strength parameters was successfully applied to number of slopes in Higashi Hiroshima
city in Hiroshima Prefecture, Japan, for hazard assessment. A typical procedure for the
investigation of a slope is summarized below.
1. Gather the geological and topographical maps of the area of interest (susceptible
valley of interest).
2. The in situ testing points are determined at both sides of the valley center from top to
the foot at 20-m intervals.
3. At each testing point, the gradient of slope needs to be measured and the LWDCPTs
are to be carried out. The soil samples will be taken at 30 cm depth for permeability
tests, and other laboratory tests.
Figure 19 shows an example of investigation carried out at a valley in Mt. Gagara.
Along the lines A and B, LWDCPTs and soil sampling were carried out. Based on the
developed relationships, shear strength parameters were determined and are illustrated in
the cross sections of lines A and B as drawn in Fig. 19b and c. In addition to that, two soil
0
0.5
1
1.5
2
25 30 35 40
Friction angle d )(
Triaxial Test
Estimated from LWDCPT
Corrected
Miyakegawa Valley
Fc = 3.9 %
0
0.5
1
1.5
2
30 35 40 45
Friction angle d )(
Triaxial Test
Estimated from LWDCPT
Corrected
Mukaihara Valley
Fc = 5.6 %
0
0.5
1
1.5
2
30 35 40 45
Friction angle d )(
Triaxial Test
Estimated from LWDCPT
Corrected
Yasuura Valley
Fc = 18.1 %
0
0.5
1
1.5
2
25 30 35 40
Friction angle d )(
Triaxial Test
Estimated from LWDCPT
Corrected
0
0.5
1
1.5
2
0 5 10 15 20
Depth(m)Depth(m)
Depth(m)Depth(m)
Depth(m)Depth(m)
Depth(m)Depth(m)
Apparent cohesion cd (kPa)
Triaxial Test
Estimated from LWDCPT
Corrected
Miyakegawa Valley
Fc = 3.9 %
0
0.5
1
1.5
2
0 5 10 15 20
Apparent cohesion cd (kPa)
Triaxial Test
Estimated from LWDCPT
Corrected
Mukaihara Valley
Fc = 5.6 %
0
0.5
1
1.5
2
0 5 10 15 20
Apparent cohesion cd (kPa)
Triaxial Test
Estimated from LWDCPT
Corrected
Yasuura Valley
Fc = 18.1 %
0
0.5
1
1.5
2
0 5 10 15 20
Apparent cohesion cd (kPa)
Triaxial Test
Estimated from LWDCPT
Corrected
Aratani Valley
Fc = 9.6 %
Fig. 18 Comparison of the experimental and estimated values of shear strength parameters
1344 Nat Hazards (2015) 75:1327–1348
123
21. samples were taken for the permeability tests from the site. Using this information, it is
possible to analyze the slope for the measured or predicted rainfall data. Tsuchida et al.
(2014) carried out a case study for the failure occurred at Shiwa, in Hiroshima Prefecture,
based on the proposed methodology and formulas and concluded that the shear strength
parameters evaluated on proposed formulas well agreed to explain its failure. The rest of
the slopes which is susceptible to failure can be well assed through the proposed meth-
odology. However, collecting the information of individual slopes is challengeable as the
number of susceptible slopes/valleys is very high in Hiroshima Prefecture. A day is
required to investigate and carryout the in situ tests in a given site. Since the proposed
formulas were developed for the weathering remnants of decomposed granite, more studies
are needed to make the validity of the developed formulas to other soils and regions.
4 Conclusions
The overall objective of this research was to find an effective methodology to investigate
the slopes susceptible to landslide disasters in Hiroshima Prefecture, Japan. Major concern
was to find the shear strength parameters spatially to analyze the stability of slopes due to
the shortcomings of the currently available methodologies. Some of such methods avail-
able in the literature are expensive and time-consuming or cannot be applicable for the
steep slopes and slopes with difficult access. Authors are proposed new methodology based
on recently developed LWDCPT. With the new method, it can be easily find the thickness
of soil profile and other terrain conditions, spacing of in situ tests, and shear strength
(a) (b) (c)
Fig. 19 Pattern categorization of a slope in Mt. Gagara and cross sections with shear strength parameters
Nat Hazards (2015) 75:1327–1348 1345
123
22. parameters required for the stability analyses. Based on the outcomes of this research,
following conclusions are drawn.
1. Six patterns of cone resistance varying along the depth were identified in the profiles
having weathering remnants of decomposed granite. The proposed six patterns were
successfully applied for the different locations and found that most of the soundings
can be fitted into one of the pattern. Therefore, proposed classification can be
successfully applied to the terrains having weathering remnants of decomposed
granite.
2. It was found that the use of newly developed LWDCPT is convenient due to its
automatic recording to a greater accuracy of penetration resistance, simplicity in
handling, and less time in completing a typical site characterization. Therefore, it has
been proposed for carrying out the site investigations in the slopes and valleys in
Hiroshima Prefecture, Japan. LWDCPT can be applied to other soils and different
regions for site characterization purposes and to obtain the shear strength parameters.
However, this needs extensive testing program as done for weathered remnants of
decomposed granite under this study.
3. A good correlation (qd = ‘Nd
3/4
) was established between the data collected from
LWDCPT and PDCPT. LWDCPT provides more reliable accurate results than
PDCPT. Also, LWDCPT was found to be more efficient than PDCPT in completing a
typical site characterization. Linear relationship was identified between SPT N value
and Nd as, Nd = 2.2 N. Based on these relationships, an approximate cross-relation
was identified between qd with SPT N value as N = 1.15qd
4/3
. The use of these
equations for other soils than for decomposed granites needs to be examined.
4. The scatter of the cone resistance at different grid spaces was quantitatively analyzed
by means of coefficient of variation (COV) and was found that COV varies 0–35 % for
all range of data. The Spherical Model was found to be the best-fitted semi-variogram
for the decomposed granitic profiles, and hence, it can be applied to evaluate the cone
resistance at unknown location. The correlated distance varies from 11 m to 30 m with
the depth increases from 0.1 to 2.5 m, respectively. This gives some idea for
determination of grid spaces in carrying out in situ investigation of natural slopes of
weathering remnants of decomposed granite.
5. The friction angle of reconstituted soils of weathering remnants of decomposed granite
was found to be linearly varied with the void ratios approximately. Fairly good linearly
varying relationships were established between void ratios and apparent cohesion
under different degrees of saturation. The equations are:
/d ¼ 52:7 À 19:2e
cd ¼ 27:5 À 0:146Sr À 14:2e
6. Based on the cone resistance data, qd, relationships were developed to calculate shear
strength parameters in terms of degrees of saturation as:
/d ¼ 29:9 þ 1:61 lnðqd5Þ þ 0:142Sr
cd ¼ 10:6 þ 1:19 lnðqd5Þ À 0:041Sr
The proposed formulas can be successfully applied to determine the shear strength
parameters for known degree of saturation. Knowing the fine content of the soils, better
1346 Nat Hazards (2015) 75:1327–1348
123
23. estimation can be made for friction angle and apparent cohesion based on the modification
factors proposed in this study.
Open Access This article is distributed under the terms of the Creative Commons Attribution License
which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the
source are credited.
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