Download or read book Constitutive Modeling the Elasto viscoplastic Behavior of Regina Clay Soil Under the Drained Stress Path Condition written by yiwei luo and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The stress-strain behavior of soft clay soil is dependent on the applied strain rate and such time dependency behavior should be considered in geotechnical engineering projects such as the bearing capacity analysis for a foundation. Most previous studies focus on elastic-viscoplastic behavior of clay soil under an undrained stress path condition. The developed constitutive models cannot simulate the strong time-dependent stress-strain relation of soft clay under the drained stress path condition. In the long-term bearing capacity analysis for a shallow foundation, the neglect of the time-dependent stress-strain relation of soft clay may result in inaccurate result. In this study, the strain-rate-dependent soil behavior is modeled using the Drucker-Prager/Cap model with the consideration of soil creep behavior. Both consolidation creep and shear creep mechanisms are considered in the modeling. A simplified approach is proposed to derive creep parameters from stress relaxation test results. The constitutive modeling is validated against experimental measurements on strain-rate-dependent behavior of Regina clay soil under the drained stress path condition. Finite element modeling on the long-term bearing capacity of a shallow foundation on soft clay is also performed. The result shows that the considering of viscoplastic behavior of clay soils does not affect the ultimate bearing capacity. However, it yields the lower bound of developed shear stress of a shallow foundation at a given vertical displacement, which is to be conservative from the engineering point of view.
Download or read book Constitutive Modeling of Soils and Rocks written by Pierre-Yves Hicher and published by John Wiley & Sons. This book was released on 2013-03-01 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: This title provides a comprehensive overview of elastoplasticity relating to soil and rocks. Following a general outline of the models of behavior and their internal structure, each chapter develops a different area of this subject relating to the author's particular expertise. The first half of the book concentrates on the elastoplasticity of soft soils and rocks, while the second half examines that of hard soils and rocks.
Download or read book Bounding Surface Elastoplasticity viscoplasticity for Clays written by Victor Nicholas Kaliakin and published by . This book was released on 1985 with total page 1052 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modelling of Soil Behaviour with Hypoplasticity written by David Mašín and published by Springer. This book was released on 2018-12-12 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explains the hypoplastic modelling framework. It is divided into two parts, the first of which is devoted to principles of hypoplasticity. First, the basic features of soil’s mechanical behaviour are introduced, namely non-linearity and asymptotic properties. These features are then incorporated into simple one-dimensional hypoplastic equations for compression and shear. Subsequently, a hypoplastic equivalent of the Modified Cam-Clay model is developed in 2D space using stress and strain invariants to demonstrate key similarities and differences between elasto-plastic and hypoplastic formulations. Lastly, the mathematical structure of hypoplastic models is explained by tracing their historical development, from the early trial-and-error models to more recent approaches. In turn, Part II introduces specific hypoplastic models for soils. First, two reference models for sand and clay are defined. After summarising their mathematical formulations, calibration procedures are described and discussed. Subsequently, more advanced modelling approaches are covered: the intergranular strain concept incorporating the effects of small strain stiffness and cyclic loading, viscohypoplasticity for predicting rate effects, soil structure to represent structured and bonded materials and soil anisotropy. The book concludes with a description of partial saturation and thermal effects: topics that are increasingly important to the disciplines of energy and environmental geotechnics. Selecting a constitutive model and its parameters is often the most important and yet challenging part of any numerical analysis in geotechnical engineering. Hypoplasticity involves a specific class of soil constitutive models, which are described in detail here. The book offers an essential resource, both for model users who need a more advanced model for their geotechnical calculations and are mainly interested in parameter calibration procedures, and for model developers who are seeking a comprehensive understanding of the mathematical structure of hypoplasticity.
Download or read book Elastic viscoplastic Modeling of Rate Dependent Behavior of Clays written by Namasivayam Sathialingam and published by . This book was released on 1991 with total page 576 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluating the Capabilities of Some Constitutive Models in Reproducing the Experimental Behaviour of Stiff Clay Subjected to Tunnelling Stress Paths written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Accurate prediction of soil behaviour around tunnel excavations is vital for the assessment of its effects on existing infrastructures and services, both underground and surface, and evaluation of risks to enable safe designs. This thesis evaluates the capabilities of four constitutive models in reproducing the intrinsic experimental behaviour of stiff clay when subjected to tunnelling-induced stress paths. Relevant stress paths have been determined from 2D and 3D finite element analysis using PLAXIS. Reconstituted Speswhite Kaolin clay specimens have been prepared from slurry, their properties investigated in detail, and tested using state-of-the-art stress path equipment and on-sample instrumentation. The soil model testing software SM2D has been used to compare the models predictions to the experimental measurements. The results have shown that there are yet many limitations in terms of accurately simulating the response of overconsolidated clay when subjected to extension, essential in tunnelling problems. Also the only model considered that has features to account for small-strain behaviour has been found to be too crude in its current state to be applied to complex geotechnical problems without further reflection. Some suggestions for improvement have been given. The results presented should help in making a more informed selection of models for design purposes.
Download or read book A New Elasto viscoplastic Model for Rate dependent Behavior of Clays written by Yixing Yuan (Ph. D.) and published by . This book was released on 2016 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt: Viscous properties of clay pertain to numerous geotechnical problems, such as excessive settlements associated with constructed fills on marine clays, or rate-dependent cyclic response of offshore foundations under wave loading. Although there are many observations on rate-dependent characteristics of clays in laboratory tests, none of the existing soil models has attained consistent descriptions of the observed strain-rate effects in shearing, or creep and relaxation in compression. This thesis develops a novel elasto-viscoplastic soil model, MIT-SR, to address these limitations. The proposed I-D formulation introduces a physically-based evolution law that attributes the macroscopic viscoplastic strain rate to an internal strain rate associated with the prior strain rate history. By varying the rate-sensitivity parameter the proposed model provides a unified framework that can describe a wide range of observed time-effects in I -D compression behavior, and resolves a long-standing dilemma regarding the coupling of creep and long-term consolidation ('Hypothesis A vs B' controversy). The framework has been further enhanced to allow the predictions of volumetric hysteretic behavior as well as the reduction of creep properties after I -D swelling. The MIT-SR soil model features a 3-D surface system, generalized hysteretic formulation and physical-based viscoplastic flow rules, which are grafted together with the framework of the prior MIT-SI elastoplastic soil model. The MIT-SR model adds 5 parameters to the prior formulation in order to represent rate-dependent soil properties. These parameters can be evaluated from a set of defined test procedures in standard laboratory devices. The proposed model has been calibrated for Resedimented Boston Blue Clay. Comparisons of predictions with experimental data have shown that the proposed model can accurately predict anisotropic stress-strain-strength properties and rate-dependent characteristics for a range of undrained shear tests. MIT-SR is the fourth generation of effective-stress soil models developed at MIT. It greatly expands the predictive capabilities of its predecessors and overcomes the limitations of existing rate-dependent soil models in the literature. The proposed model has many potential applications in geotechnical analyses, particularly in problems that involve considerable strain rate effects (e.g., pile penetrations in clays) or long-term ground movements (e.g., embankments founded on soft clays).
Download or read book Observed Stress strain Behaviour of Remoulded Saturated Clay and Examination of Two Constitutive Models written by Michał Topolnicki and published by . This book was released on 1987 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Implementation and Evaluation of a Recently Developed Rate dependent Effective Stress Soil Model MIT SR written by Mauro Giuliano Sottile and published by . This book was released on 2016 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reliable modeling of rate-dependency in soil properties remains a major challenge for accurate solutions of many geotechnical problems. Although there are many sources of experimental data concerning rate dependent properties of clays, most pre-existing soil models have been found to have severe predictive limitations. Yuan (2016) developed a new elasto-viscoplastic model, MIT-SR, for rate-dependent behavior of clays. The model unifies the existing elasto-plastic framework from prior MIT soil models (3-D surface system and generalized hysteretic formulation) with a physically-based evolution law that attributes the macroscopic viscoplastic strain to an internal strain rate related to the prior strain rate history. MIT-SR has the capability of describing a wide range of observed time-effects within a unified framework and resolves the long-stranding dilemma regarding creep effects at field scale (i.e., Hypothesis A vs B). This thesis implements MIT-SR model to evaluate strain rate effects on two longstanding geotechnical problems: insitu soil characterization from pressuremeter tests and long-term performance of embankments on soft clays. The first part of this research presents a review of the constitutive model framework and discuss the implementation and validation in non-linear finite element analyses using a User Defined Material (UMAT) in the ABAQUSTM program. Part two consists of the investigation of how disturbances (modeled using Strain Path framework; Baligh, 1985) and strain rate effects (modeled by MIT-SR) affect the results of the Full Displacement or cone-pressuremeter (FDPM) and self-boring pressuremeters (SBPM) for Resedimented Boston Blue Clay (RBBC). The results show that that disturbances of the stress field play a vital role in the interpretation undrained shear strength. For the FDPM case, using the same expansion rate, the disturbed NC RBBC can have as low as 40% of the undrained shear strength of the undisturbed NC RBBC. In contrast, for the SBPM case, the disturbed NC RBBC tend to have a slightly higher undrained shear strength (approximately 10%) than the undisturbed NC RBBC. The third part consists of a re-analysis of a well-instrumented test embankment built on a 40m deep layer of Boston Blue Clay. Finite element analyses of embankment performance are conducted using coupled consolidation with the MIT-SR effective stress model. The results were compared with previous numerical results using MIT-E3 presented by Ladd et al. (1994). Overall, MIT-SR contributes a significant improvement in predictions of settlements, but does not significantly improve predictions of lateral spreading. The overall results suggest that the dependent creep properties play only a secondary role in the performance of this particular test embankment.
Download or read book An Elastic viscoplastic Constitutive Model for Soil written by Curtis G. Kelln and published by . This book was released on 2008 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: The concepts of elasticity and viscoplasticity were used to develop an elastic-viscoplastic (EVP) constitutive model for soil. The mathematical description of viscoplastic straining includes a measure of both effective stress and the corresponding volumetric packing of the soil particles. The model is able capture the dependence of stress-strain relationships and undrained shear strength on strain rate, the development of irrecoverable plastic strains at constant stress, which is creep, and the relaxation of stresses at constant strain. A Newton-Raphson solution scheme with a stress point algorithm was used to implement the EVP soil model in a finite element program. The algorithms and assumptions required to implement the solution scheme are provided. Verification of the solution scheme is achieved by using it to analyze typical boundary value problems. A case history is developed for a geotextile reinforced highway embankment constructed on a soft estuarine deposit installed with prefabricated vertical drains. The EVP soil model was then used to simulate the measured deformation response. The numerical simulations closely matched the temporal changes in pore water pressures and surface settlement beneath the centerline and shoulder of the embankment. More importantly, the elastic-viscoplastic model simulated the pattern and the magnitudes of the lateral deformations beneath the toe of the embankment;... a notoriously difficult aspect of modelling the deformation response of soft soils. The simulations were achieved using a small set of material constants that can easily be obtained from standard laboratory tests. The research validates the use of the EVP model for problems involving heterogeneous soft soil deposits beneath loading from a geotechnical structure"--Abstract.
Download or read book Bounding Surface Hypo plasticity Model for Granular Soils and Its Applications written by Zhi-Liang Wang and published by . This book was released on 1990 with total page 562 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Non linearity and Small Strain Behaviour in Lacustrine Clay written by Sophie Messerklinger and published by vdf Hochschulverlag AG. This book was released on 2006 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanical Behavior and Constitutive Modelling of Natural Structured Soils written by Ken'ichi Soga and published by . This book was released on 1994 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Visco Plastic Behaviour of Geomaterials written by N.D. Cristescu and published by Springer Science & Business Media. This book was released on 1994-06-07 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aim of this book is to present to researchers and engineers a description of the present knowledge on the viscoplasticity of geomaterials, considering the experimental and theoretical aspects and the applications to relevant problems. First, the laboratory tests performed in order to quantitatively assess the theological properties of rocks are illustrated, describing the equipments used in modern rock mechanics laboratories and the proper testing procedures. Part of the presentation is devoted to the description of constitutive creep laws having different degrees of accuracy and complexity. The book covers also problems related to the application of numerical solution procedures to rock/soil mechanics situations in which the slow deformation of geomaterials is to be taken into account.
Download or read book Introduction to Hypoplasticity written by D. Kolymbas and published by CRC Press. This book was released on 2000-01-01 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book aims to give the reader a short, tractable and as far as possible complete introduction to the young theory of hypoplasticity, which is a new approach to constitutive modelling of granular media in terms of rational continuum mechanics.
Download or read book An Investigation of Certain Aspects of Stress strain Relationships for Clay Soils written by Dominique Namy and published by . This book was released on 1970 with total page 546 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Adapting the Modified Cam Clay Constitutive Model to the Computational Analysis of Dense Granular Soils written by Jose Alejandro Arvelo G. and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The computational constitutive Modified Cam Clay Model (MCCM) was developed at Cambridge to study the behavior of clays and has been proven to be effective. In this study, this model is extended to the case of dense sands to analyze the accuracy of the stress-strain behavior. This analysis is based on triaxial test data applied to remolded and compacted sand samples under drained conditions.
