Mechanics of Granular Media and Its Application in Civil Enginenering


Book Description

Systematic approach to the construction of a probabilistic simulation model for distribution of pressure in granular media. Pressure fields & compressive deformations from that model presented for a thrustless granular medium & homogeneous or stratified earth foundation. General solutions incorporating partial cases of thrustless & thrusting granular media.




Mechanics of Granular Materials: An Introduction


Book Description

This textbook compiles reports written by about 35 internationally recognized authorities, and covers a range of interests for geotechnical engineers. Topics include: fundamentals for mechanics of granular materials; continuum theory of granular materials; and discrete element approaches.




Behaviour of Granular Materials


Book Description

This book presents a complete and comprehensive analysis of the behaviour of granular materials including the description of experimental results, the different ways to define the global behaviour from local phenomena at the particle scale, the various modellings which can be used for a D.E.M. analysis to solve practical problems and finally the analysis of strain localisation. The concepts developed in this book are applicable to many kinds of granular materials considered in civil, mechanical or chemical engineering.




The Physics Of The Deformation Of Densely Packed Granular Materials


Book Description

This book is of interest for those that are concerned professionally with granular materials: civil engineers, geologists and geophysicists, chemical engineers, pharmacists, food technologists, agriculturalists, biologists and astronomers.Granular materials play a role in nearly all human activities. For example, users of sand, from children in sandpits to sophisticated geotechnical engineers, know that it is a fascinating — and to some extent, unpredictable — material. In addition to sand, which itself may be of many compositions, there are various types of materials including gravel, fine-particle aggregates as employed in cosmetics, pharmaceuticals, dust, crushed rock and granules that occur in a domestic environment, such as breakfast cereals, sugar, salt and (instant or ground) coffee granules.The aim of the book is to present a theory that explains the physics behind the phenomena during the deformation of densely packed granular media. The physics that describes such features is rather subtle and is developed from the micro to macro level (the latter is the continuum mechanics level that is used in practical applications). It requires the analysis of anisotropy and the heterogeneity of the packing evaluated against the background of a frictional inter-particle interaction.




Advances in Multi-Physics and Multi-Scale Couplings in Geo-Environmental Mechanics


Book Description

Advances in Multi-Physics and Multi-Scale Couplings in Geo-Environmental Mechanics reunites some of the most recent work from the French research group MeGe GDR (National Research Group on Multiscale and Multiphysics Couplings in Geo-Environmental Mechanics) on the theme of multi-scale and multi-physics modeling of geomaterials, with a special focus on micromechanical aspects. Its offers readers a glimpse into the current state of scientific knowledge in the field, together with the most up-to-date tools and methods of analysis available. Each chapter represents a study with a different viewpoint, alternating between phenomenological/micro-mechanically enriched and purely micromechanical approaches. Throughout the book, contributing authors will highlight advances in geomaterials modeling, while also pointing out practical implications for engineers. Topics discussed include multi-scale modeling of cohesive-less geomaterials, including multi-physical processes, but also the effects of particle breakage, large deformations on the response of the material at the specimen scale and concrete materials, together with clays as cohesive geomaterials. The book concludes by looking at some engineering problems involving larger scales. - Identifies contributions in the field of geomechanics - Focuses on multi-scale linkages at small scales - Presents numerical simulations by discrete elements and tools of homogenization or change of scale




IUTAM Symposium on Mechanics of Granular and Porous Materials


Book Description

This volume constitutes the Proceedings of the IUT AM Symposium on Mechanics of Granular and Porous Materials, held in Cambridge from 15th to 17th July 1996. The objectives were: 1. To review existing experimental results and practical phenomena on the flow and compaction of particulate media; 2. To review the current state of constitutive models, and their implementation for predicting the macroscopic response. 3. Identification of the shortcomings of existing models and procedures in understanding practical phenomena. The Symposium brought together the research communities of solid mechanics, materials science, geomechanics, chemical engineering and mathematics to review current knowledge of the flow and compaction of granular and porous media. The meeting emphasised the development and use of constitutive laws to model practical processes such as mixing, drainage and drying, compaction of metal and ceramic powders and soils, and instabilities associated with these processes. A common theme was to develop constitutive models from an understanding of the underlying physical mechanisms of deformation and fracture. It was particularly rewarding to find that the separate research communities came together during the meeting and came to a consensus as to the main mechanisms of deformation and failure of particulate and porous solids.




Physics of Dry Granular Media


Book Description

Dry granular materials, such as sand, sugar and powders, can be poured into a container like a liquid and can also form a pile, resisting gravity like a solid, which is why they can be regarded as a fourth state of matter, neither solid nor liquid. This book focuses on defining the physics of dry granular media in a systematic way, providing a collection of articles written by recognised experts. The physics of this field is new and full of challenges, but many questions (such as kinetic theories, plasticity, continuum and discrete modelling) also require the strong participation of mechanical and chemical engineers, soil mechanists, geologists and astrophysicists. The book gathers into a single volume the relevant concepts from all these disciplines, enabling the reader to gain a rapid understanding of the foundations, as well as the open questions, of the physics of granular materials. The contributors have been chosen particularly for their ability to explain new concepts, making the book attractive to students or researchers contemplating a foray into the field. The breadth of the treatment, on the other hand, makes the book a useful reference for scientists who are already experienced in the subject.







Distinct Element Modelling in Geomechanics


Book Description

Linear mathematical assumptions for procedures in other branches of engineering have little relevance for geoengineering, which must accommodate non-linear behaviors. Contributors to eight papers apply the breakthrough numerical modeling Distinct Element Method (Cundall, late 1960s). The design philosophy for structures or excavations in geotechnical engineering is different from that followed for fabricated materials like steel and concrete. The designer has little data both with regard to geological weaknesses and strength and deformation characteristics of materials before finalizing the designs. Also these characteristics vary from place to place. In-situ stresses due to gravity and tectonics and transient forces imposed due to rainfall and earthquakes make the matter more complicated. The pore waters carry the load initially before passing it on to the solids. For the analytical procedure, to be realistic, it should account for large displacements and non-linear behaviour including strain-softening. Because of these considerations, the designers have followed procedures based on simplifying assumptions such as linear, small strain, elastoplastic behaviour. Numerical procedures based on such assumptions, though very popular in other branches of engineering, have made little impact in geo-engineering. An attempt has been made in this book to compile the recent use of distinct element codes for solutions of some of the problems in geomechanics — particularly those involving excavations. It is hoped that it will provide an opportunity for the fraternity of geotechnical engineers to appreciate the opening of new frontiers in the use of computers for solving more challenging geotechnical problems.




The Coupled Theory of Mixtures in Geomechanics with Applications


Book Description

Geomaterials consist of a mixture of solid particles and void space that may be ?lled with ?uid and gas. The solid particles may be di?erent in sizes, shapes, and behavior; and the pore liquid may have various physical and chemical properties. Hence, physical, chemical or electrical interaction - tween the solid particles and pore ?uid or gas may take place. Therefore, the geomaterials in general must be considered a mixture or a multiphase material whose state is described by physical quantities in each phase. The stresses carried by the solid skeleton are typically termed “e?ective stress” while the stresses carried by the pore liquid are termed “pore pressure. ” The summation of the e?ective stress and pore pressure is termed “total stress” (Terzaghi, 1943). For a free drainage condition or completely undrained c- dition, the pore pressure change is zero or depends only on the initial stress condition; it does not depend on the skeleton response to external forces. Therefore, a single phase description of soil behavior is adequate. For an intermediate condition, however, some ?ow (pore pressure leak) may take place while the force is applied and the skeleton is under deformation. Due to the leak of pore pressure, the pore pressure changes with time, and the e?ective stress changes and the skeleton deforms with time accordingly. The solution of this intermediate condition, therefore, requires a multi-phase c- tinuum formulations that may address the interaction of solid skeleton and pore liquid interaction.