Download or read book Study of Desiccation Cracking and Fracture Properties of Clay Soils written by Warnakulasuriya D Susanga M Costa and published by . This book was released on 2010 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: The thesis focuses on the development of shrinkage cracking in clay soils upon drying and the determination of fracture properties of clay soils as applicable to analysis of desiccation cracking phenomenon. The results and conclusions were drawn from comprehensive experimental work analysed drawing from Classical Soil Mechanics, Fracture Mechanics, Unsaturated Soil Mechanics and Mechanics of Materials with the aid of powerful image analysis techniques. Attempts were made to fill the gaps in the existing knowledge related to scope of the thesis as identified by a detailed study on the previous works. Three types of soils were used for the work presented in this thesis: Merri-Creek clay, Werribee clay and milled fine sand. The former two are naturally available materials in the Melbourne region. The last material was sourced from a commercial dealer. Potato starch was also used in desiccation tests as an alternative material to examine the crack patterns different from clays. Qualitative and quantitative studies were carried out using these materials aiming to acquire deeper understanding of the cracking mechanisms. Effects of desiccation rate, specimen thickness and particle size on crack patterns were studied. The influence of stress distribution and flaw distribution on crack initiation was also discussed. Image analysis techniques were used extensively to investigate the deformations of soil particles during drying. Shrinkage characteristics and onset of crack initiation were closely studied with displacement vector fields and strain isochrones. Interesting observations were made during these studies which led to deeper understanding of the subject, especially in relation to the mechanisms of crack initiation and associated modelling approaches. Fracture properties of Werribee clay was investigated using SENB beam test. Fracture toughness, fracture energy of Werribee clay was measured using three methods. An attempt was made to explain the behaviour of these parameters with the water content. Finally, an innovative test method to determine the J-integral was introduced. The test is specially designed to determine the J-integral of desiccating soils.

Download or read book Fracture Propagation of Cohesive Soils Under Tensile Loading and Desiccation written by Benjamin Michael Shannon and published by . This book was released on 2013 with total page 614 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tensile fracture of clay soils either due to loading or due to desiccation is a common problem encountered in many geotechnical, geoenvironmental and resources engineering applications such as in compacted clay liners, dams, embankments, slopes, seabed trenching for pipeline placement and in mine tailings. However, the fundamental understanding of this process and its modelling capability has not yet advanced satisfactorily. This research intends to fill this gap, following on the past and concurrent research undertaken on this topic by Monash Geomechanics Group. The current research is to develop fundamental characteristics of fracture properties, develop relevant measuring and analysis techniques and provide the basis for theoretical modelling. The research undertaken comprised of three main laboratory testing stages, and analytical, numerical, theoretical and predictive modelling. Five main different soils were used throughout this thesis including: Werribee clay, Merri Creek clay, Altona North clay, Prestige NY kaolin clay and HR1F kaolin clay. The first three are naturally available in Victoria whereas the two kaolin clays are sourced from commercial dealers in NSW. A comprehensive soil properties database was compiled for all soils tested. Advanced image analysis techniques were extensively used throughout testing to capture strains caused by loading and/or desiccation and determine fracture propagation surfaces. Tensile crack surfaces of compacted soils with varying compaction pressure were analysed on a macro scale to identify voids and aggregate conglomeration. The tensile strength of soils was rigorously tested for mechanical loading and desiccation induced cracking. Mechanically loaded samples were examined for effects of preconsolidation pressure, compaction pressure, soil type and water content at failure. Tensile loading tests were completed using the indirect diametrical tensile (IDT) test. Results on tensile strength found from past literature were compiled and analysed using the MPK framework for volumetric behaviour of unsaturated soils. A line of optimum tensile strength was found from void ratio and moisture ratio for various soil types. An extensive restrained shrinkage desiccation test (Monash desiccation cracking test) was introduced to determine tensile strength, fracture toughness, shrinkage strains and suction from changing water content. Tests were modelled using analytical and numerical modelling. A theoretical and predictive model was determined using MIT and critical state methods based on the restrained shrinkage desiccation test. Fracture properties of clay soils were analysed under four-point bending notch beams and cylindrical ring tests. Linear elastic fracture mechanics, elastic-plastic fracture mechanics and plastic fracture mechanics were all used in calculating fracture energy and toughness. Numerical modelling was undertaken using FLAC3D and UDEC codes to model laboratory and analytical test results for restrained shrinkage tests. UDEC was used to model fracture properties from laboratory restrained tests. Finally, comparisons between different tensile strength tests and numerical models were examined.

Download or read book Multiphysical Testing of Soils and Shales written by Lyesse Laloui and published by Springer Science & Business Media. This book was released on 2012-08-22 with total page 331 pages. Available in PDF, EPUB and Kindle. Book excerpt: Significant advancements in the experimental analysis of soils and shales have been achieved during the last few decades. Outstanding progress in the field has led to the theoretical development of geomechanical theories and important engineering applications. This book provides the reader with an overview of recent advances in a variety of advanced experimental techniques and results for the analysis of the behaviour of geomaterials under multiphysical testing conditions. Modern trends in experimental geomechanics for soils and shales are discussed, including testing materials in variably saturated conditions, non-isothermal experiments, micro-scale investigations and image analysis techniques. Six theme papers from leading researchers in experimental geomechanics are also included. This book is intended for postgraduate students, researchers and practitioners in fields where multiphysical testing of soils and shales plays a fundamental role, such as unsaturated soil and rock mechanics, petroleum engineering, nuclear waste storage engineering, unconventional energy resources and CO2 geological sequestration.

Download or read book Modelling of Desiccation Crack Depths in Clay Soils written by Rathnayaka Mudiyanselage Sasika Dilrukshi Wijesooriya and published by . This book was released on 2012 with total page 323 pages. Available in PDF, EPUB and Kindle. Book excerpt: Desiccation cracking is a major problem in many fields. In addition to introducing speedy pathways for water ingress, cracks can also compromise the structural integrity of the geo structures. In this regard, prediction of the depth of cracking is an important aspect in evaluating system performance. Modelling of desiccation cracks is a major concern for the past few decades. Despite the numerous attempts to model the crack depths, no comprehensive modelling method is available. In this study, an attempt has been made to model the desiccation crack depths using analytical and numerical approaches.The thesis presents a review of the literature identifying the gaps of the knowledge in this field, numerical modelling of desiccation crack depths under various conditions for different soils and laboratory experimentation to support the numerical model. The existing theoretical methods used to analyse desiccation crack depths and new methods have been developed to describe the predictions from the numerical program. Further the cyclic change of climate conditions are considered for developing the numerical model. Finally a new approach is used to predict the crack depths in which moisture content change was used instead of suction. Finally a more rigorous approach of predicting crack depths incorporating cohesive properties at the crack is presented using the computer program UDEC.The results from the numerical approach are presented and discussed in the thesis. The crack depths are compared with either theoretical results or a bench-mark model, highlighting pros and cons of current approaches. More accurate crack depths agreeing with the published field observation data can be predicted when using the moisture content change instead of suction as a model parameter. Furthermore, cohesive properties of the crack should be considered for fracture modelling provided that soils are not subjected to extreme dry conditions.However, it is recommended to conduct comprehensive field experimentation to measure the desiccation crack depths and compare the results with the numerical modelling predictions of the same soil in same field conditions to draw fully validated conclusions.

Download or read book Fundamental Relationships of Crack Formation in Expansive Clay Soils written by Peter Daniel Fisher and published by . This book was released on 1994 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Contemporary Issues in Soil Mechanics written by Sayed Hemeda and published by Springer. This book was released on 2018-10-27 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is of interest to practical engineers. It discusses some contemporary issues related to soil mechanics in earthwork projects which are critical components in civil construction and often require detailed management techniques and unique solution methods to address failures. Being earth bound, earthwork is influenced by geomaterial properties at the onset of a project. Hence, an understanding of the in-situ soil properties is essential. Slope stability is a common problem facing earthwork construction, such as excavations and shored structures. Analytical methods for slope stability remain critical for researchers due to the mechanical complexity of the system. Striving for better earthwork project managements, the geotechnical engineering community continues to find improved testing techniques for determining sensitive properties of soil and rock, including stress-wave based, non-destructive testing methods. To minimize failure during earthwork construction, past case studies and data may reveal useful lessons and information to improve project management and minimize economic losses. This volume discusses these aspects using appropriate methods in a simple way. The volume is based on the best contributions to the 2nd GeoMEast International Congress and Exhibition on Sustainable Civil Infrastructures, Egypt 2018 – The official international congress of the Soil-Structure Interaction Group in Egypt (SSIGE).

Download or read book The Properties and Utilization of Cracking Clay Soils written by J. W. McGarity and published by . This book was released on 1984 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Simulation of Shrinkage and Cracks in Clayey Soils on Drying Paths written by Wenqing Cheng and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Clay soil is widely distributed on the Earth's surface, and because it is cheap and readily available, clay soil has been widely used as a building material for a very long history. Furthermore, clay can be used as not only a natural barrier in the dam cores, but also a matrix for the storage of radioactive wastes because of its retention properties. The mechanical behavior of clay materials is complex, one of the difficulties is that it is sensitive to water. During the desiccation process, clay soils undergo shrinkage, which can cause cracking. The aim of this thesis is, initially, to develop a numerical approach capable of reproducing the phenomenon of shrinkage, the distribution of water content as well as that of suction. In a second step, based on Coussy's theory for unsaturated porous media, and the mechanics of unsaturated soils, a constitutive law will be proposed to describe the behavior observed during desiccation. Finally, to reproduce the cracks distribution, based on the extended finite element method (X-FEM). The realization of numerical simulation is based on the analysis of the desiccation experiments of clay soils in laboratory. The application of the digital image correlation (DIC) technology in the desiccation experiments makes the study on the desiccation process in clay soils more accurate. The experimental results show that the clay soils will generate the theoretical shrinkage deformation caused by its own water loss in the drying path. This deformation in simulation can be related to the water content of clays through the Fredlund function. The desiccation shrinkage of clay soils has an anisotropic phenomenon. The coefficient of shrinkage ratio is used to describe this phenomenon in simulation. One of the ways to construct the constitutive of the initially saturated soft clays during drying could be in using two independent stress tensors which will enable the decomposition of total strain tensor into strain tensor due to drying shrinkage (induced part due to suction variation) and a “mechanical” strain tensor due to the total stress variation. Mechanical strain tensor can be related to total stress by using stiffness matrix. In fact, the initially saturated clay soil resistance increases during desiccation. The result of cracking in the soil under controlled suction is the result of competitions between increased soil resistance and damage caused by shrinkage during desiccation. The soil moisture crack initiation criterion will be based on soil damage and resistance. The criterion of crack propagation, meanwhile, will be based on the theory of conservation of energy. To reproduce the cracks distribution, based on X-FEM. Weibull's law will be used to consider the heterogeneous distribution of the soil. After digital model validation, applications in the geotechnical field are then considered.

Download or read book Effect of Environmental and Geometrical Factors on Microstructure Desiccation Cracking and Carbon Dioxide Flux in Clays written by Charles Clayton Goodman and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Studying the effects of extreme conditions, such as high temperatures and low humidity, on soil properties is important to various disciplines, including geotechnical engineering, soil science, waste management, crop management, and ceramics. The goal of this research is to investigate the effect of environmental and geometrical factors on microstructure, desiccation cracking, and CO2 flux in clays. The objectives of this research are threefold. (1) Understand the effects of temperature on the microstructure of clay soils; (2) develop a standardized procedure for studying desiccation cracking in a laboratory setting with reliable and repeatable results; and (3) develop an environmental chamber capable of monitoring CO2 flux through a soil sample large enough to accommodate a fully developed crack network. To accomplish these objectives, an array of laboratory testing was conducted. First, this study examines the effects of extreme temperatures on the microstructural properties of clay using FESEM, cation-exchange capacity (CEC) tests, thermal gravimetric analysis (TGA), and Brunauer-Emmett-Teller (BET) surface area analyzer. Second, a standardized procedure for producing accurate and repeatable laboratory tests on the desiccation cracking of soils is presented. The procedure includes specifications for sample collection, material preparation and characterization (including microstructural properties), and the determination of a representative elemental area (REA) for a fully developed crack network. Finally, a new climatic chamber capable of controlling temperature and relative humidity is designed and tested. The chamber can monitor CO2 flux through a fully developed crack network, enabling fundamental research on the relationship between desiccation cracking and the oxidation of soil organic carbon. The key findings indicate a dependency of soil microstructure on temperature changes. CEC and BET surface area significantly decrease with temperatures beyond 100̊C, indicating a relationship that needs further study. Additionally, compacted and slurry cracking behavior was found to be sensitive to boundary geometry and sample thickness. A REA was identified for each slurry sample thickness. The procedures of this research can be repeated for other soil types and used to connect existing and future research to improve understanding of desiccation cracking behavior, and to study the effects of desiccation cracking on other important geo-environmental phenomena.

Download or read book Desiccation in Clay Soils written by Construction Research Communications Ltd and published by . This book was released on 1996 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Desiccation in clay soils can result in shrinkage of the soil and subsidence of the ground; this may lead to damage to buildings. As the soil re-hydrates, it can swell, resulting in ground heave; this may also cause damage to buildings. In many ground investigations, it is important to establish the extent and depth of any desiccation but this is not always easy. This Digest describes the most commonly used techniques for detecting desiccation and gives guidance on how to use the results of some of these techniques to estimate heave potential.

Download or read book Multilevel Modeling of Secure Systems in QoP ML written by Bogdan Księżopolski and published by CRC Press. This book was released on 2015-07-02 with total page 734 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introducing the Quality of Protection Modeling Language (QoP-ML), this book provides for the abstraction of security systems while maintaining emphasis on the details of quality protection . It delineates the steps used in cryptographic protocol and introduces a multilevel protocol analysis that expands current understanding. Every operation defined by QoP-ML is described within parameters of security metrics, therefore evaluating the impact of the operation on the entire system's security.

Download or read book A Study of Desiccation Cracking in Clay Layers at Landfills written by Tara Lynn O'Leary and published by . This book was released on 1999 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Desiccation Cracks and their Patterns written by Lucas Goehring and published by John Wiley & Sons. This book was released on 2016-03-09 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bringing together basic ideas, classical theories, recent experimental and theoretical aspects, this book explains desiccation cracks from simple, easily-comprehensible cases to more complex, applied situations. The ideal team of authors, combining experimental and theoretical backgrounds, and with experience in both physical and earth sciences, discuss how the study of cracks can lead to the design of crack-resistant materials, as well as how cracks can be grown to generate patterned surfaces at the nano- and micro-scales. Important research and recent developments on tailoring desiccation cracks by different methods are covered, supported by straightforward, yet deep theoretical models. Intended for a broad readership spanning physics, materials science, and engineering to the geosciences, the book also includes additional reading especially for students engaged in pattern formation research.

Download or read book Vertisols and Technologies for their Management written by N. Ahmad and published by Elsevier. This book was released on 1996-12-11 with total page 566 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vertisols, one of the eleven established soil orders, are clay soils with unusual and interesting properties. They cover more than 350 million hectares of land in the world and in tropical Africa alone there are over 100 million hectares. Because of their very small particle size and high surface area, these soils have higher physical and chemical reactivity than other soils. Their interaction with agrochemicals/industrial wastes, has been, increasingly, the subject of research especially in the last two decades. Vertisols create special problems when used for engineering purposes. This book is intended to provide comprehensive and state-of-the-art information about Vertisols worldwide. Special attention is given to the use and management of soils such as fertilizer use, crop selection, soil tillage, water restriction on land including irrigation, and soil erosion. A special chapter has been added to deal with geotechnical engineering of Vertisols. Vertisols have great potential for agricultural production but many, especially in the developing world, are underutilized due to a lack of understanding regarding their behaviour and management. This book is written by leading scientists worldwide. It is expected that this monograph will be of great use to soil scientists and agronomists, graduate and senior graduate students. Improvement of their management may solve the current food deficiency in the world.

Download or read book Theory of Flow and Fracture of Solids written by Arpád Nádai and published by . This book was released on 1950 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proceedings of a Symposium on the Properties and Utilization of Cracking Clay Soils written by Armidale Symposium on the Properties and Utilization of Cracking Clay Soils (Australia, 1981) and published by . This book was released on 1984 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proceedings of the 4th Congr s International de G otechnique Ouvrages Structures written by Hoang-Hung Tran-Nguyen and published by Springer. This book was released on 2017-10-20 with total page 1181 pages. Available in PDF, EPUB and Kindle. Book excerpt: This proceedings volume for the 4th international conference CIGOS 2017 (Congrès International de Géotechnique - Ouvrages - Structures) presents novel technologies, solutions and research advances, making it an excellent guide in civil engineering for researchers, students, and professional engineers alike. Since 2010, CIGOS has become a vital forum for international scientific exchange on civil engineering. It aims to promote beneficial economic partnerships and technology exchanges between enterprises, worldwide institutions and universities. Following the success of the last three CIGOS conferences (2010, 2013 and 2015), the 4th conference was held at Ho Chi Minh City University of Technology, Ho Chi Minh City (Saigon), Vietnam on 26 to 27 October 2017. The main scientific themes of CIGOS 2017 were focused on ‘New Challenges in Civil Engineering’.