Effects of Specimen Type on the Residual Strength of Clays and Clay Shales


Book Description

This investigation was an examination of the effects of testing apparatus, specimen type and density, normal stress, and sequence of loading on the residual strength of various clays and clay shales. Annular shear and repeated direct shear tests were conducted on intact shale specimens with precut failure planes, while comparison rotational shear tests were conducted on the same shale material subjected to various degrees of remolding. Test results indicate that comparable residual strengths can be obtained, regardless of equipment type and procedure or degree of remolding. Supplemental annular shear tests on residual clay and silty sand show that precutting of the failure plane or the specimen density has no effect on the ?r' value. The residual friction angle is independent of stress history and normal load [when greater than 2 kg/cm2 (1.96 x 105 Pa)].




Engineering Properties of Clay Shales


Book Description

This report compares various laboratory procedures and equipment used for determining the residual strength of clay shales. The effects of testing apparatus, specimen type, normal load, and rate of displacement on the residual strength of various clay shales were evaluated by relations between residual strength and Atterberg limits, grain size, and mineralogy were examined. (Modified author abstract).







The Effect of Rate of Displacement on Measuring the Residual Strength of Clays


Book Description

Rotation shear tests were performed with a device developed to measure residual shear strengths of clays clay shales, on annual specimens of remolded Bearpaw shale and remolded London clay. Rates of displacement in comparative tests, are expressed in peripheral velocities of the annular specimens. (Author).




Residual Strength of Clay and Clay-shales by Rotation Shear Tests


Book Description

The objectives of this investigation were to develop a rotation shear machine to measure the residual shear strength (constant shearing resistance at which material undergoes continuous deformation under a constant state of effective stress) of clays and clay-shales; investigate testing errors; and measure residual shear strengths of representative types of highly plastic clays and clay-shales. In the rotation shear test, torque is applied to the bottom of the specimen and two force transducers measure the couple necessary to maintain the upper half of the specimen stationary. Disc-shaped or annular specimens with thicknesses from 0.1 to 2.5 cm and outside diameters of 7.11 cm can be tested. Variations in residual shear strength were investigated for normally consolidated versus overconsolidated specimens, for specimens sheared at different rates of peripheral displacement, and for specimens prepared by several different remolding procedures. (Author Modified Abstract).




Shear Behavior of Composite Soils


Book Description

This book has the purpose of developing an understanding of the factors determining and influencing the shear behavior of soils, with emphasis on composite soils, as they are the most encountered materials in geological and geotechnical engineering in mountainous areas. This objective is reached by examining the soil compressibility, structure of shear zone and its evolution, and water content of shear zone and shear mode of soils together with analyses of the influences of intrinsic properties, e.g. Atterberg limits, particle size distribution, particle shape, and testing conditions, e.g. normal stress and shearing rate. An in-depth review is presented in an approximately chronological order and covers almost all the factors that are believed to influence the mechanical behavior of soils. The equipment and test techniques for shear strength of soils are detailed. The residual shear behavior of composite soil is investigated by means of a systematic laboratory testing program using a large ring shear apparatus and an intermediate direct shear box. The Fast Fourier Transform is employed for the first time to analyze the fluctuations of measured shearstress and discovers the close relationships with both intrinsic properties of soils and testing conditions. Although the book is aimed primarily at researchers in geological and geotechnical engineering, it contains material of interest to students of geology and soil science and also should be a useful reference for practicing engineers faced with composite soils.




Slope Stability and Stabilization Methods


Book Description

A major revision of the comprehensive text/reference Written by world-leading geotechnical engineers who share almost 100 years of combined experience, Slope Stability and Stabilization, Second Edition assembles the background information, theory, analytical methods, design and construction approaches, and practical examples necessary to carry out a complete slope stability project. Retaining the best features of the previous edition, this new book has been completely updated to address the latest trends and methodology in the field. Features include: All-new chapters on shallow failures and stability of landfill slopes New material on probabilistic stability analysis, cost analysis of stabilization alternatives, and state-of-the-art techniques in time-domain reflectometry to help engineers plan and model new designs Tested and FHA-approved procedures for the geotechnical stage of highway, tunnel, and bridge projects Sound guidance for geotechnical stage design and planning for virtually all types of construction projects Slope Stability and Stabilization, Second Edition is filled with current and comprehensive information, making it one of the best resources available on the subject-and an essential reference for today's and tomorrow's professionals in geology, geotechnical engineering, soil science, and landscape architecture.










Geotechnics for Sustainable Infrastructure Development


Book Description

This book presents 09 keynote and invited lectures and 177 technical papers from the 4th International Conference on Geotechnics for Sustainable Infrastructure Development, held on 28-29 Nov 2019 in Hanoi, Vietnam. The papers come from 35 countries of the five different continents, and are grouped in six conference themes: 1) Deep Foundations; 2) Tunnelling and Underground Spaces; 3) Ground Improvement; 4) Landslide and Erosion; 5) Geotechnical Modelling and Monitoring; and 6) Coastal Foundation Engineering. The keynote lectures are devoted by Prof. Harry Poulos (Australia), Prof. Adam Bezuijen (Belgium), Prof. Delwyn Fredlund (Canada), Prof. Lidija Zdravkovic (UK), Prof. Masaki Kitazume (Japan), and Prof. Mark Randolph (Australia). Four invited lectures are given by Prof. Charles Ng, ISSMGE President, Prof.Eun Chul Shin, ISSMGE Vice-President for Asia, Prof. Norikazu Shimizu (Japan), and Dr.Kenji Mori (Japan).