Towards A Unified Soil Mechanics Theory

With the application of the effective stress concept, the strength and volumetric behavior of saturated materials was clearly understood. For the case of unsaturated materials, a universally accepted effective stresses equation is still under debate. However, the use of the effective stress concept to develop constitutive models for unsaturated soils is becoming increasingly popular not only because the hydro-mechanical coupling observed in these materials is implicit in the formulation but also because simpler and more precise models can be established. Towards A Unified Soil Mechanics Theory demonstrates that the same strength and volume change equations used in saturated soil mechanics can be used for the case of unsaturated soils. In other words, the constitutive models developed for saturated soils can be used for unsaturated materials once the effective stress equation has been defined. In this book, an analytical equation for the effective stress for unsaturated soils is established. This equation requires the knowledge of the superficial area of solids affected by the capillary phenomenon. In other words, we need to know how water distributes in the pores of the soil. This distribution can be modeled using a solid-porous model built on a regular network. However, the size of the network required to correctly simulate the structure of a small soil sample cannot be managed with a common PC. For that reason, a probabilistic porous-solid model is developed. This model uses the pore size distribution in the form of a probabilistic function which in addition to the Laplace equation and the principle of continuity can be expressed as the probability of a pore of certain size to be filled or dry at suction during a wetting or drying path, respectively. In this way, the soil-water retention curves can be simulated and the effective stress at any suction during wetting or drying processes can be determined. Based on this approach, it is shown that unsaturated soils behave under the same principles for strength and volumetric behavior as saturated soils. This revised edition brings additional information about an elastoplastic framework for expansive soils, hydro-mechanical coupling and a fully coupled model. The additional chapters also cover the experimental parameters used to derive the models. An updated set of references and a list of abbreviations is also included in this edition. Towards A Unified Soil Mechanics Theory paves the way for a universal theory of soil mechanics. The volume will be a valuable reference to civil engineers, earth scientists and hydrologists interested in soil mechanics at both academic and professional levels.

Towards A Unified Soil Mechanics Theory demonstrates mathematical models for saturated and unsaturated soils by defining the effective stress equation. Chapters present hydraulic models that simulate water distribution in pores. Parameters from these models are then used to demonstrate the use of an effective stress equation to understand the mechanics of soils that have different material constitutions. Key Features: -Sequentially explains soil modeling techniques for easy understanding -Demonstrates the use of an effective stress equation based on data from porous-solid models. -Explains how porous-solid models can simulate the soilwater retention curves of materials. -Establishes an elastoplastic framework for the volumetric behavior of unsaturated soils that is used to simulate the phenomenon of collapse upon wetting and the behavior of expansive soils. -Explains the practical application of fully a coupled hydro-mechanical (critical state) soil model -Includes scientific references for further reading The third edition includes additional information on retention curves in deforming curves, the application of a coupled hydro-mechanical model simulating undrained tests and the behavior of soils during static compaction, and the use of a porous-solid model to develop a fully analytical equation for the relative hydraulic conductivity of soils. The new chapters also cover the experimental parameters used to derive the models. This edition also updates material from previous editions, and adds new scientific references. Towards A Unified Soil Mechanics Theory paves the way for a universal theory of soil mechanics that has a wide range of applications. The book is a valuable reference to civil engineers, geotechnical engineers, earth scientists and hydrologists interested in soil mechanics at both academic and professional levels.

While many introductory texts on soil mechanics are available, most are either lacking in their explanations of soil behavior or provide far too much information without cogent organization. More significantly, few of those texts go beyond memorization of equations and numbers to provide a practical understanding of why and how soil mechanics work. Based on the authors’ more than 25 years of teaching soil mechanics to engineering students, Soil Mechanics Fundamentals presents a comprehensive introduction to soil mechanics, with emphasis on the engineering significance of what soil is, how it behaves, and why it behaves that way. Concise, yet thorough, the text is organized incrementally, with earlier sections serving as the foundation for more advanced topics. Explaining the varied behavior of soils through mathematics, physics and chemistry, the text covers: Engineering behavior of clays Unified and AASHTO soil classification systems Compaction techniques, water flow and effective stress Stress increments in soil mass and settlement problems Mohr’s Circle application to soil mechanics and shear strength Lateral earth pressure and bearing capacity theories Each chapter is accompanied by example and practicing problems that encourage readers to apply learned concepts to applications with a full understanding of soil behavior fundamentals. With this text, engineering professionals as well as students can confidently determine logical and innovative solutions to challenging situations.

This book focuses on the unified solutions and analysis for the problems in soil mechanics based on the unified strength theory, which is a new theory on the yield and failure of materials under multi-axial stresses. Then, it provides a system of yield and failure criteria adopted for most materials, from metallic materials to rocks, concretes, soils, polymers, etc. It includes the Tresca criterion, Mohr–Coulomb theory, and Mises criterion as well, which are special cases or linear approximation of the UST.

How Does Soil Behave and Why Does It Behave That Way? Soil Mechanics Fundamentals and Applications, Second Edition effectively explores the nature of soil, explains the principles of soil mechanics, and examines soil as an engineering material. This latest edition includes all the fundamental concepts of soil mechanics, as well as an introduction to foundation engineering, including coverage of site exploration, shallow and deep foundation design, and slope stability. It presents the material in a systematic, step-by-step manner, and contains numerous problems, examples, and solutions. New to the Second Edition: The revised text expands the contents to include an introductory foundation engineering section to make the book cover the full range of geotechnical engineering. The book includes three new chapters: Site Exploration, Deep Foundations, and Slope Stability. This text: Provides an introductory chapter on soil mechanics Explores the origin and description of soils and discusses soil shapes and gradations Presents the unique characteristics of clays Details soil classifications by the Unified Soil Classification System (also ASTM) and by the American Association of State Highway and Transportation Officials (AASHTO) Highlights laboratory and field compaction techniques, including field specification and density testing,, and the CBR (California Bearing Ratio) method Discusses the flow of water through soils, defining hydraulic heads, as well as the two-dimensional flow net technique and a systematic approach to compute boundary water pressures Examines the concept of effective stress and its applications to various soil mechanics problems Explores stress increments in a soil mass due to various types of footing load on the ground Presents Terzaghi’s one-dimensional consolidation theory and its applications Covers Mohr’s circle from geotechnical perspectives with use of the pole, which is utilized in chapters relating to shear strength and lateral earth pressure Addresses the shear strength of soils, failure criteria, and laboratory as well as field shear strength determination techniques Evaluates at-rest earth pressure and the classic Rankine and Coulomb active and passive pressure theories and present critical review of those methods Reviews introductory foundation engineering and site exploration Describes the bearing capacity theory and, as an application, the shallow foundation design procedure Covers deep and shallow foundation design procedures Explains slope stability problems and remediation procedures, and more Soil Mechanics Fundamentals and Applications, Second Edition is a concise and thorough text that explains soil’s fundamental behavior and its applications to foundation designs and slope stability problems and incorporates basic engineering science knowledge with engineering practices and practical applications.

Although theoretical in character, this book provides a useful source of information for those dealing with practical problems relating to rock and soil mechanics - a discipline which, in the view of the authors, attempts to apply the theory of continuum to the mechanical investigation of rock and soil media. The book is in two separate parts. The first part, embodying the first three chapters, is devoted to a description of the media of interest. Chapter 1 introduces the main argument and discusses the essence of the discipline and its links with other branches of science which are concerned, on the one hand, with technical mechanics and, on the other, with the properties, origins, and formation of rock and soil strata under natural field conditions. Chapter 2 describes mechanical models of bodies useful for the purpose of the discourse and defines the concept of the limit shear resistance of soils and rocks. Chapter 3 gives the actual properties of soils and rocks determined from experiments in laboratories and in situ. Several tests used in geotechnical engineering are described and interconnections between the physical state of rocks and soils and their rheological parameters are considered.The second part of the book considers the applications of various theories which were either first developed for descriptive purposes in continuum mechanics and then adopted in soil and rock mechanics, or were specially developed for the latter discipline. Chapter 4 discusses the application of the theory of linear viscoelasticity in solving problems of stable behaviour of rocks and soils. Chapter 5 covers the use of the groundwater flow theory as applied to several problems connected with water movement in an undeformable soil or rock skeleton. Chapter 6 is a natural expansion of the arguments put forward in the previous chapter. Here the movement of water is regarded as the cause of deformation of the rock or soil skeleton and the consolidation theory developed on this basis is presented in a novel formulation. Some new engineering solutions are also reported. The seventh chapter is devoted to the limit state theory as applied to the study of the mechanical behaviour of soils and rocks. It presents some new solutions and methods which include both static and kinematic aspects of the problem, and some original effective methods for investigating media of limited cohesion. The final chapter gives a systematic account of the mechanics of highly dispersed soils, commonly called clays.

Plasticity and Geotechnics is the first attempt to summarize and present in a single volume the major achievements in the field of plasticity theory for geotechnical materials and its applications to geotechnical analysis and design. The book emerges from the author’s belief that there is an urgent need for the geotechnical and solid mechanics community to have a unified presentation of plasticity theory and its application to geotechnical engineering.