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 Experimental Study of Silty Clay Plane Strain Tri-axial Test under RTC Path and Modified Cam-clay Model

2018 ◽  
Vol 4 (3) ◽  
pp. 518
Author(s):  
Tao Cheng ◽  
Yi Zhang ◽  
Keqin Yan
Keyword(s):  
Plane Strain ◽  
Stress Path ◽  
Physical Parameters ◽  
Silty Clay ◽  
Model Framework ◽  
Loading Test ◽  
Clay Model ◽  
Modified Cam Clay ◽  
Institute Of Technology ◽  
Cam Clay

The character of geomaterials is affected by stress path remarkably. Under different stress paths, the stress-strain characteristics of geomaterials are difference. For the unloading path in existing engineering situation, the physical parameters and constitutive model is usually determined by loading test. The path to uninstall the actual project conditions which may be a larger error. Therefore, this work proceeding from the actual project, deep excavation of the lateral unloading condition is analysed. The tests of CTC path and RTC path on silty clay in Huangshi city of china by multi-path tri-axial plane strain are carried on in the geotechnical Engineering Laboratory of Huangshi Institute of Technology. Then, the phenomenon under the two stress paths are compared with each other and describing the differences between them. The mechanical properties in the RTC stress path is analyzed mainly. Based on the Cam-Clay model framework, then derived this material yield equation based on Cam-clay model, Laiding the foundation for the numerical analysis.

scholarly journals Evaluation of additional confinement for three-dimensional geoinclusions under general stress state

2020 ◽  
Vol 57 (3) ◽  
pp. 453-461 ◽  
Author(s):  
Piyush Punetha ◽  
Sanjay Nimbalkar ◽  
Hadi Khabbaz
Keyword(s):  
Stress State ◽  
Plane Strain ◽  
Principal Stress ◽  
Three Dimensional ◽  
Axisymmetric Stress State ◽  
Proposed Model ◽  
Strength And Stiffness ◽  
Semi Empirical ◽  
Minor Principal Stress

Three-dimensional cellular geoinclusions (e.g., geocells, scrap tires) offer all-around confinement to the granular infill materials, thus improving their strength and stiffness. The accurate evaluation of extra confinement offered by these geoinclusions is essential for predicting their performance in the field. The existing models to evaluate the additional confinement are based on either a plane-strain or axisymmetric stress state. However, these geoinclusions are more likely to be subjected to the three-dimensional stresses in actual practice. This note proposes a semi-empirical model to evaluate the additional confinement provided by cellular geoinclusions under the three-dimensional stress state. The proposed model is successfully validated against the experimental data. A parametric study is conducted to investigate the influence of input parameters on additional confinement. Results reveal that the simplification of the three-dimensional stress state into axisymmetric or plane-strain condition has resulted in inaccurate and unreliable results. The extra confinement offered by the geoinclusion shows substantial variation along the intermediate and minor principal stress directions depending on the intermediate principal stress, infill soil, and geoinclusion properties. The magnitude of additional confinement increases with an increase in the geoinclusion modulus. The findings are crucial for accurate assessment of the in situ performance of three-dimensional cellular geoinclusions.

The Use of a Mechano-Lattice Analogy for Determining the Abrading Stresses in Sliding Rubber

1971 ◽  
Vol 44 (3) ◽  
pp. 758-770
Author(s):  
W. O. Yandell
Keyword(s):  
Principal Stress ◽  
Poisson’S Ratio ◽  
Sliding Friction ◽  
Poisson's Ratio ◽  
Large Strains ◽  
Damping Factor ◽  
Stress Strain ◽  
Minor Principal Stress

Abstract A rigorous mechano-lattice analogy analysis for calculating the hysteretic sliding friction of and stresses in rubber sliding on variously shaped asperities is presented. The analysis allows large strains and any Poisson's Ratio, rigidity or damping factor of the rubber. The analysis was used to calculate the distributions of minor principal stress in rubber sliding over smooth and frictional prisms with different sharpnesses and over a cylinder. The potentially disruptive stress regions were thus revealed and compared. The effect of changes in the Poisson's Ratio and of the damping factor of the rubber were also examined. It was postulated that the fine texture generates more stress-strain hysteretic heat which may lead to the more rapid abrasion observed by some workers.

UNDRAINED SHEAR STRENGTH OF K0 CONSOLIDATED SOFT CLAYS UNDER TRIAXIAL AND PLANE STRAIN CONDITIONS

2014 ◽  
Vol 06 (03) ◽  
pp. 1450032 ◽  
Author(s):  
QIUSHENG WANG ◽  
XIULI DU ◽  
QIUMING GONG
Keyword(s):  
Shear Strength ◽  
Plane Strain ◽  
Yield Surface ◽  
Critical State ◽  
Volumetric Strain ◽  
Stress Path ◽  
Undrained Shear Strength ◽  
Triaxial Tests ◽  
Soft Clays ◽  
Undrained Shear

Theoretical formulas for predicting the undrained shear strength of K0 consolidated soft clays under the stress path related to triaxial and plane strain tests are presented within the framework of critical state soil mechanics. An inclined elliptical yield surface is adopted to take account of the initial anisotropic stress state. The undrained strength is determined by combining the undrained stress path in the volumetric stress–strain space and the initial yield surface in the deviator-mean stress space. The derived mathematical expressions are functions of the critical state frictional angle, the plastic volumetric strain ratio and the overconsolidation ratio, which can be simplified into the solutions for isotropically consolidated clays under triaxial tests or under plane strain tests. The results calculated by using the theoretical formulas obtained in this paper are in good agreement with the available collected test results. It indicates that these new formulas are applicable to triaxial and plane strain tests on normally and lightly to moderately overconsolidated soft clays.

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

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°.

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 Asaksa ◽  
Kohji Tokimatsu ◽  
Kazuaki Iwasaki ◽  
Yasuhiro Shamoto
Keyword(s):  
Strain Path ◽  
Stress Path ◽  
Triaxial Tests ◽  
Stress Strain ◽  
Strain Relation ◽  
Stress Strain Relation ◽  
Simple Stress

scholarly journals The Application of Improved Duncan-Chang Model in Unloading Soil

2014 ◽  
Vol 8 (1) ◽  
pp. 410-415 ◽  
Author(s):  
Yi He ◽  
Xuejun Chen
Keyword(s):  
Triaxial Test ◽  
Stress Path ◽  
Model Parameters ◽  
Silty Clay ◽  
True Triaxial Test ◽  
Stress Strain ◽  
Foundation Pit ◽  
Foundation Soil ◽  
Strain Relationship ◽  
Chang Model

On the basis of the representative samples of silty clay found in Wuhan, China, the lateral unloading of soil’s stress path produced by excavating foundation pit engineering, was simulated by triaxial experiment. A series of consolidated- drained true triaxial test and normal triaxial test were conducted. According to the results of tests, the parameter of the Duncan-Chang Model was determined. A modulus formula was used for the foundation soil in the lateral unloading stress path tests to replace the modulus formula of Duncan-Chang Model based on the σ3 =const . Moreover, the Duncan- Chang hyperbola nonlinear elastic constitutive model was used to simulate the plane strain test. A method to improve the ability of Duncan-Chang model in order to take into account the effects of the intermediate principal stress on the strength and deformation was presented as well as all the model parameters were also determined. The adaptability of the model for unloading the stress path was verified by comparing the theoretical stress-strain relationship and empirical stress-strain relationship.

Unloading Triaxial Experimental Study on Stress Path of Excavated Soil Slope

2011 ◽  
Vol 243-249 ◽  
pp. 2797-2801 ◽  
Author(s):  
Yan Gang Zhang ◽  
Kun Yong Zhang ◽  
Wang Lin Li ◽  
Qiao Zhen Shi
Keyword(s):  
Principal Stress ◽  
Triaxial Compression ◽  
Constitutive Models ◽  
Confining Pressure ◽  
Stress Path ◽  
Soil Mass ◽  
Soil Slope ◽  
Compression Tests ◽  
Excavation Process ◽  
Major Principal Stress

The current research was implemented to study the practical unloading stress path that the slope mass experienced during the excavation process, which is very important in the stress and strain numerical analysis. Series of unloading tests were carried out under different confining pressure. During the test process, the minor principal stress was kept decreasing, while the major principal stress was kept unchanged to simulate the stress path in some locations of the soil slope, such as at the top of the slope. The corresponding conventional triaxial compression tests were also carried out as comparison. It is shown that there are many differences between the unloading and loading tests. Through analyzing, the tests results could be applied in the development of unloading constitutive models of excavation soil mass. Also, such unloading tests data are valuable in calibration and verification of the current existing popularly used models.

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