Effect of consolidation history and stress path on hyperbolic stress–strain relations

1985 ◽  
Vol 22 (2) ◽  
pp. 172-176 ◽  
Author(s):  
Y. P. Vaid
Keyword(s):  
Stress Path ◽  
Triaxial Tests ◽  
Soil Deformation ◽  
Test Results ◽  
Stress Strain ◽  
Deviator Stress ◽  
Strain Behaviour ◽  
Stress Variable ◽  
Anisotropic Consolidation ◽  
Soil Behaviour

The hyperbolic approximation of the stress–strain behaviour of soil based on the results of conventional triaxial tests, which is used in incremental elastic analysis of soil deformation problems, is shown to be inapplicable for representing soil behaviour under anisotropic consolidation and different stress paths. Test results on a normally consolidated clay are presented to show that a separate hyperbolic representation of stress–strain behaviour is possible for each consolidation history and stress path if increment in deviator stress after consolidation, rather than deviator stress, is used as the stress variable. Hyperbolic parameters are thus shown to depend on test type.

Effects of Stress Path and Stress History on the Stiffness of Reconstituted London Clay

1986 ◽  
Vol 2 (1) ◽  
pp. 139-144 ◽  
Author(s):  
J. H. Atkinson ◽  
J. S. Evans ◽  
D. Richardson
Keyword(s):  
Stress Path ◽  
Triaxial Tests ◽  
Soil Parameters ◽  
Stress History ◽  
Strain Behaviour ◽  
Reconstituted Soil ◽  
Path Dependent ◽  
London Clay ◽  
Soil Behaviour

AbstractSoil behaviour is stress history dependent and stress path dependent and soil parameters, particularly those for stress-strain behaviour, measured in conventional triaxial tests may not represent the behaviour of soil in many civil engineering works.To obtain more realistic parameters it may be necessary to conduct laboratory tests which more closely represent in situ conditions before and during construction.The paper describes equipment developed at The City University to carry out stress path tests simply and economically. A series of CU triaxial tests and stress path tests on reconstituted soil illustrate the dependence of measured soil parameters on stress history and stress path.

Stress Path Tests on 100 mm Diameter Samples

1986 ◽  
Vol 2 (1) ◽  
pp. 133-137
Author(s):  
J. H. Atkinson ◽  
D. B. Clinton
Keyword(s):  
Stress Path ◽  
Triaxial Tests ◽  
Test Results ◽  
Design Problems ◽  
Strain Behaviour ◽  
Engineering Design Problems ◽  
Geotechnical Design ◽  
Pore Pressure Response ◽  
The City ◽  
Test Stress

AbstractThe use of stress path tests is discussed in relation to geotechnical design, and a description is given of the triaxial test stress path apparatus developed at The City University.Test results are presented from a series of triaxial tests following stress paths commonly encountered in engineering design problems. These are compared with the results of conventional triaxial tests.The stress-strain behaviour and pore pressure response of soil are shown to be very much dependent on the stress path followed, and the advantages of using stress-controlled loading in triaxial tests is demonstrated.

scholarly journals An evolutionary modelling approach to predicting stress-strain behaviour of saturated granular soils

2018 ◽  
Vol 35 (8) ◽  
pp. 2931-2952 ◽  
Author(s):  
Alireza Ahangar Asr ◽  
Asaad Faramarzi ◽  
Akbar A. Javadi
Keyword(s):  
Axial Strain ◽  
Volumetric Strain ◽  
Triaxial Tests ◽  
Granular Soils ◽  
Unified Framework ◽  
Stress Strain ◽  
Content Type ◽  
Deviator Stress ◽  
Strain Behaviour ◽  
Model Predictions

PurposeThis paper aims to develop a unified framework for modelling triaxial deviator stress – axial strain and volumetric strain – axial strain behaviour of granular soils with the ability to predict the entire stress paths, incrementally, point by point, in deviator stress versus axial strain and volumetric strain versus axial strain spaces using an evolutionary-based technique based on a comprehensive set of data directly measured from triaxial tests without pre-processing. In total, 177 triaxial test results acquired from literature were used to develop and validate the models. Models aimed to not only be capable of capturing and generalising the complicated behaviour of soils but also explicitly remain consistent with expert knowledge available for such behaviour.Design/methodology/approachEvolutionary polynomial regression (EPR) was used to develop models to predict stress – axial strain and volumetric strain – axial strain behaviour of granular soils. EPR integrates numerical and symbolic regression to perform EPR. The strategy uses polynomial structures to take advantage of favourable mathematical properties. EPR is a two-stage technique for constructing symbolic models. It initially implements evolutionary search for exponents of polynomial expressions using a genetic algorithm (GA) engine to find the best form of function structure; second, it performs a least squares regression to find adjustable parameters, for each combination of inputs (terms in the polynomial structure).FindingsEPR-based models were capable of generalising the training to predict the behaviour of granular soils under conditions that have not been previously seen by EPR in the training stage. It was shown that the proposed EPR models outperformed ANN and provided closer predictions to the experimental data cases. The entire stress paths for the shearing behaviour of granular soils using developed model predictions were created with very good accuracy despite error accumulation. Parametric study results revealed the consistency of developed model predictions, considering roles of various contributing parameters, with physical and engineering understandings of the shearing behaviour of granular soils.Originality/valueIn this paper, an evolutionary-based data-mining method was implemented to develop a novel unified framework to model the complicated stress-strain behaviour of saturated granular soils. The proposed methodology overcomes the drawbacks of artificial neural network-based models with black box nature by developing accurate, explicit, structured and user-friendly polynomial models and enabling the expert user to obtain a clear understanding of the system.

Stress–strain behaviour of weathered weak rock in middle-sized triaxial tests

2006 ◽  
Vol 43 (10) ◽  
pp. 1096-1104 ◽  
Author(s):  
De'an Sun ◽  
Tugen Feng ◽  
Hajime Matsuoka
Keyword(s):  
Triaxial Test ◽  
Confining Pressure ◽  
Triaxial Tests ◽  
Weak Rock ◽  
Test Results ◽  
Compression Tests ◽  
Stress Strain ◽  
Strain Behaviour ◽  
Undisturbed Samples ◽  
Strain Relationship

A middle-sized triaxial test apparatus for a specimen 20 cm in height and 10 cm in diameter was developed to measure the deformation and strength of weak rock or gravel. High-quality undisturbed samples of a weathered weak rock were taken from a dam site by a core drilling method. To avoid damage to the structure of the weak rock due to saturation of specimens as a result of measuring volume change through the water change in a burette, the lateral deformation of specimens was directly measured in the unsaturated condition using three rings mounted on the specimen. Using the developed triaxial test apparatus, isotropic compression tests and consolidated–drained triaxial compression tests were performed on unsaturated or saturated undisturbed samples under confining pressures of 49, 98, 196, 392, 539, and 683 kPa. The test results show that the stress–strain relationship of the weathered weak rock under both unsaturated and saturated conditions is strongly influenced by the confining pressure when the confining pressure is less than 392 kPa, and the stress–strain behaviour becomes similar to that of normally consolidated clay when the confining pressure is greater than 392 kPa. Comparison of results of triaxial tests on unsaturated and saturated specimens shows that the saturated samples become somewhat weak. The test results also show that the bonding and stress history largely influence the stress–strain relationship at small strain levels.Key words: weathered weak rock, microstructure, undisturbed sample, deformation, strength, triaxial test, unsaturated sample.

An experimental examination of the critical state and other similar concepts for granular soils

1995 ◽  
Vol 32 (6) ◽  
pp. 1065-1075 ◽  
Author(s):  
J. Chu
Keyword(s):  
Critical State ◽  
Friction Angle ◽  
Stress Path ◽  
Dense Medium ◽  
Triaxial Tests ◽  
Granular Soils ◽  
Test Results ◽  
Dense Sand ◽  
Strain Behaviour ◽  
Series Of Experiments

Measuring the critical state parameters of dense granular soil by drained triaxial tests is problematic, as significant nonhomogeneous deformations can develop prior to approaching a critical state. This leads to further questions on the verification of the critical state concept for granular soils. In this study a new testing method, which enables the critical state of dense sand to be measured in the homogeneous deformation region, was adopted to measure the critical state of dense sand and to examine the critical state concept. A series of experiments was carried out to measure the critical state for dense, medium dense, and loose sand. The test results show that although a unique critical state curve may exist, the critical state friction angle is not constant but stress level dependent. The other similar concepts, namely, the phase transformation state, the characteristic state, and the steady state, were also examined, and the relationships among these states were established. Key words : critical state, granular soils, stress path, stress–strain behaviour, triaxial test.

Analysis of the Mechanic Behavior and Rutting of Asphalt Concrete Using a Sand Model

1999 ◽  
Vol 15 (4) ◽  
pp. 177-184
Author(s):  
Ming-Lou Liu
Keyword(s):  
Asphalt Concrete ◽  
Stress Path ◽  
Plasticity Model ◽  
Test Results ◽  
Research Subjects ◽  
Stress Strain ◽  
Strain Behavior ◽  
Strain Relationship ◽  
Concrete Materials ◽  
Relationship Of

AbstractThe stress-strain relationship of the sand and asphalt concrete materials is one of the most important research subjects in the past, and many conctitutive laws for these materials have been proposed in the last two decades. In this study, the Vermeer plasticity model is modified and used to predict the behavior of the sand and asphalt concrete materials under different stress path conditions. The results show that the predictions and test results agree well under different stress path conditions. However, the orignal Vermeer model can not predict the stress-strain behavior of the asphalt concrete. Finally, the modified Vermeer plasticity model is incorporated with the pavement rutting model to predict the rut depth of pavement structure under traffic loadings.

scholarly journals A SIMPLE STRESS-STRAIN RELATION BASED ON STRESS-PATH BEHAVIOR IN STRAIN-PATH CONTROLLED TRIAXIAL TESTS

2003 ◽  
Vol 43 (2) ◽  
pp. 55-68 ◽  
Author(s):  
YOSHIHARU ASAKA ◽  
KOHJI TOKIMATSU ◽  
KAZUAKI IWASAKI ◽  
YASUHIRO SHAMOTO
Keyword(s):  
Strain Path ◽  
Stress Path ◽  
Triaxial Tests ◽  
Stress Strain ◽  
Strain Relation ◽  
Stress Strain Relation ◽  
Simple Stress

A deep retaining structure in till and sand. Part I: Stress path effects

1983 ◽  
Vol 20 (1) ◽  
pp. 120-130 ◽  
Author(s):  
L. V. Medeiros ◽  
Z. Eisenstein
Keyword(s):  
Plane Strain ◽  
Principal Stress ◽  
Stress Path ◽  
Triaxial Tests ◽  
Silty Clay ◽  
Stress Strain ◽  
Retaining Structure ◽  
Major Principal Stress ◽  
Minor Principal Stress ◽  
Passive Compression

Laboratory investigation of the stress–strain behaviour of glacial till (stiff silty clay) and dense preglacial sand have been carried out. Special attention has been devoted to investigation of the influence of different stress paths on the stress–strain response of these materials. Since these tests were performed primarily for an analytical study of the behaviour of a deep retaining structure, the stress paths chosen for testing were typical of stress conditions for this field situation. Triaxial and plane strain drained tests on till were run in passive compression (with increasing major principal stress and constant minor principal stress) and in active compression (with constant major principal stress and decreasing minor principal stress). On the sand, only triaxial tests were carried out. These experiments were in passive compression and in active extension (with decreasing major principal stress and constant minor principal stress).The results of different tests were compared at corresponding stress and strain levels. They indicated an appreciably decreased stiffness along the passive compression stress path compared with that in the active compression and active extension tests. Also, a comparison between the triaxial and plane strain tests for the till showed a marked influence of the intermediate principal stress. Although the results were intended for use in a stress path dependent, nonlinear elastic analysis they are discussed and explained in terms of a more general elastoplastic model of soil behaviour. Keywords: stress–strain relationship, stress path, laboratory testing, stiff clay, dense sand.

scholarly journals Stress–Strain Strength Characteristics of Undisturbed Granite Residual Soil Considering Different Patterns of Variation of Mean Effective Stress

2021 ◽  
Vol 11 (4) ◽  
pp. 1874
Author(s):  
Rongjun Shu ◽  
Lingwei Kong ◽  
Bingheng Liu ◽  
Juntao Wang
Keyword(s):  
Effective Stress ◽  
Stress Path ◽  
Strength Characteristics ◽  
Triaxial Tests ◽  
Residual Soil ◽  
Residual Soils ◽  
Stress Strain ◽  
Tropical Regions ◽  
Granite Residual Soil ◽  
Pattern Of Variation

Granite residual soil is one of the most frequently encountered problem soils in tropical regions, whose mechanical behavior heavily depends on the pattern of variation of mean effective stress (p’) during shearing, which can be classified into three categories: increasing-p’, constant-p’, and decreasing-p’. Unfortunately, so far, the stress–strain strength characteristics of granite residual soils have been studied mainly under increasing-p’ stress paths, although it is very likely to encounter stress paths with decreasing p’ in practice, especially in excavation engineering. Moreover, most pertinent research has focused on remolded granite residual soils, whereas undisturbed specimens have not yet received enough attention. In this paper, stress path triaxial tests considering different patterns of variation of mean effective stress were conducted on an undisturbed granite residual soil. Subsequently, a variable termed loading angle was introduced to quantitatively represent stress path. The influences of stress path on the Mohr–Coulomb strength parameters, deformation characteristics, ductility, and shearing stiffness were analyzed, with an emphasis on the role of pattern of variation of mean effective stress. The experimental results show that friction angle of the soil increases while cohesion decreases with the increase in loading angle. The increase in loading angle leads to less volume contraction and smaller failure strain. During shearing, the soil exhibited a less brittle response under stress paths with smaller loading angles. The initial secant shear modulus first decreased and then increased as the loading angle increased, with the minimum shearing stiffness occurring at a certain loading angle lying between 90° and 123.7°.

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