Generalized stress-path-dependent soil behaviour with a new hollow cylinder torsional apparatus

1990 ◽  
Vol 27 (5) ◽  
pp. 601-616 ◽  
Author(s):  
Y. P. Vaid ◽  
A. Sayao ◽  
Enhuang Hou ◽  
D. Negussey
Keyword(s):  
Principal Stress ◽  
Hollow Cylinder ◽  
Path Dependence ◽  
Stress Path ◽  
Dense Sand ◽  
Deformation Response ◽  
Stress Rotation ◽  
Path Dependent ◽  
Offshore Wave ◽  
Soil Behaviour

A new hollow cylinder torsional shear apparatus is described. The apparatus is suitable for investigating soil behaviour under generalized stress paths, including principal stress rotations, characteristic of earthquake and offshore-wave loadings. A new, more rational assessment of stress nonuniformity across the wall of the hollow cylinder specimen is made, and the "no go" regions of the stress space are delineated that limit stress nonuniformity to acceptable levels. Operation of the apparatus and experimental procedures for tests on reconstituted specimens of sand are described. Typical results of drained tests on loose and dense sand are presented to illustrate the capabilities of the apparatus as a general stress-path loading device and to highlight the stress-path dependence of soil behaviour, in particular, the deformation response to principal stress rotations. Key words: hollow cylinder apparatus, generalized stress paths, principal stress rotation, sand, deformations.

Behaviour of loose sand under simultaneous increase in stress ratio and principal stress rotation

1993 ◽  
Vol 30 (6) ◽  
pp. 953-964 ◽  
Author(s):  
Dharmapriya Wijewickreme ◽  
Yoginder P. Vaid
Keyword(s):  
Stress State ◽  
Principal Stress ◽  
Hollow Cylinder ◽  
Stress Ratio ◽  
Stress Path ◽  
Simultaneous Increase ◽  
Strain Response ◽  
Principal Stress Rotation ◽  
Stress Increment ◽  
Stress Rotation

The drained behaviour of loose sands under simultaneous increase in stress ratio and principal stress rotation is investigated. The hollow cylinder torsional device, which permits independent control of four stress parameters, namely effective mean normal stress [Formula: see text], stress ratio R, intermediate principal stress parameter b, and the inclination ασ of the major principal effective stress [Formula: see text] to the vertical, is adopted as the testing device. Drained tests carried out on saturated sand indicate that deformations under increasing R and ασ are path independent, if the final stress state is within the approximate bounds of R < 2 and ασ < 45°. With increasing stress ratio R and (or) principal stress rotation, deformations gradually become path dependent. Once loaded to a stress state within the domain R < 2 and ασ < 45°, the strain response under subsequent principal stress rotation is shown to be independent of the previous loading history. It is demonstrated that the strain response under any general increasing R − ασ path in the domain of R < 2 and ασ < 45° can be predicted using the results of a limited number of tests characterizing that domain. Strain increment direction αΔε is shown to be approximately coincident with and totally governed by the stress increment direction αΔσ, when the stress increment direction αΔσ is preferentially inclined towards the vertical deposition direction. Key words : sand behaviour, hollow cylinder torsional device, principal stress rotation, stress-path testing.

Effect of intermediate principal stress on the deformation response of sand

1996 ◽  
Vol 33 (5) ◽  
pp. 822-828 ◽  
Author(s):  
A Sãyao ◽  
Y P Vaid
Keyword(s):  
Principal Stress ◽  
Hollow Cylinder ◽  
Stress Path ◽  
B Value ◽  
Shear Loading ◽  
Intermediate Principal Stress ◽  
Experimental Program ◽  
Stress Strain ◽  
Deformation Response ◽  
Strain Behaviour

An experimental investigation of the relevance of the intermediate principal stress (σ2) on the deformation response of a sand is presented. The effects of σ2 are conveniently studied through the nondimensional stress parameter b = (σ2 – σ3)/(σ1 – σ3). A series of stress path tests was performed on Ottawa sand specimens in a hollow cylinder torsional shear device. The experimental program includes shear loading at different values of b, and special b tests, in which b was continuously varied at different stress directions. It is shown that the b value may have a significant influence on the stress–strain response of sand, depending on the loading conditions. Key words: hollow cylinder tests, generalized stress paths, sand, stress–strain behaviour, intermediate principal stress.

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.

Influence of Initial Anisotropy, Stress Path and Principal Stress Rotation on Monotonic Behavior of Clean and Mixed Sands

2020 ◽  
Vol 857 ◽  
pp. 417-430
Author(s):  
Kazem Fakharian ◽  
Farzad Kaviani Hamedani
Keyword(s):  
Principal Stress ◽  
Stress Path ◽  
Silica Sand ◽  
Large Strains ◽  
Principal Stress Rotation ◽  
Soil Behavior ◽  
Stress Rotation ◽  
Fabric Evolution ◽  
Initial Anisotropy

It is widely accepted that soil behavior is complicated taking into account soil anisotropy owing to the fact that this phenomenon arises from oriented soil fabric or structure forged in the deposition stage. In this study, a review of major findings of authors’ previous studies are presented with the main focus on soil anisotropy using extensive experimental results incuding Triaxial (TXT), Simple Shear (SSA), and Hollow Cylinder (HCA) apparatus. Effects of initial anisotropy, fabric evolution, stress path, principal stress rotation and intermediate stress state are evaluated for a crushed silica sand. In addition, the effects of Portland cement content and granulated rubber contents on anisotropic behavior of the sand are investigated. Bender elments are mounted on triaxial specimens both in vertical and horizontal directions to measure the shear wave velocity and hence maximum shear modulus at the end of consolidation as well as during shearing up to large strains at critical state condition, as an index of evaluating the fabric evolution. The effects of principal stress rotation and stress paths reveals the crucial role of soil anisotropy on the behavior of clean sand. However, adding either cement or granulated rubber to the sand has considerably decreased anisotropy.

Behaviour of recompacted residual soils in a constant shear stress path

2010 ◽  
Vol 47 (6) ◽  
pp. 648-661 ◽  
Author(s):  
S. M. Junaideen ◽  
L. G. Tham ◽  
K. T. Law ◽  
F. C. Dai ◽  
C. F. Lee
Keyword(s):  
Shear Stress ◽  
Soil Mechanics ◽  
Stress Path ◽  
Experimental Program ◽  
Published Data ◽  
Residual Soils ◽  
Constant Shear ◽  
Constant Shear Stress ◽  
Path Dependent ◽  
Soil Behaviour

The significance of studying soil behaviour in a constant shear stress path to understand rain-induced slope failures and debris flows has long been recognized. Studies with constant shear tests have, however, been limited, and some past results from undisturbed soils appear to show stress path–dependent volume change behaviour. The present study systematically investigates the behaviour of recompacted residual soils in a constant shear stress path using a comprehensive experimental program. It is shown that the results of this test program and previously published data can be interpreted using the concepts of critical-state soil mechanics.

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