Stress path effects on the strength behaviour of a layered soil

1980 ◽  
Vol 17 (4) ◽  
pp. 603-607 ◽  
Author(s):  
M. Krishna Murthy ◽  
T. S. Nagaraj ◽  
A. Sridharan
Keyword(s):  
Experimental Investigation ◽  
Effective Stress ◽  
Volume Change ◽  
Stress Path ◽  
Layered Soil ◽  
Shear Behaviour ◽  
Compression Tests ◽  
Stress Strain ◽  
Strain Behaviour ◽  
Stress Parameters

An experimental investigation dealing with the influence of stress path on the shear behaviour of a layered soil prepared in the laboratory is described. Specimens trimmed in vertical and horizontal directions have been sheared under three different stress paths in compression and extension tests. Either in compression or extension, the stress–strain behaviour of the specimens with both orientations was apparently the same, although the volume change behaviour was different. The effective stress parameters C′ and [Formula: see text]′ were found to be unique and independent of the stress path and two principal orientations. However, the values of [Formula: see text]′ in extension tests were 6–7° higher than those in compression tests.

Prediction of Stress-Strain Response Using Rotational Multiple Yield Surface Framework in Malaysian Residual Soil

2020 ◽  
Vol 843 ◽  
pp. 132-137
Author(s):  
Asmidar Alias ◽  
Mohd Jamaludin Md Noor ◽  
Abdul Samad Abdul Rahman
Keyword(s):  
Shear Strength ◽  
Effective Stress ◽  
Volume Change ◽  
Yield Surface ◽  
Axial Strain ◽  
The Body ◽  
Residual Soil ◽  
Strain Response ◽  
Stress Strain ◽  
Soil Volume

Soil settlement is normally quantified using conventional soil volume change models which are solely based on the effective stress and the role of shear strength is ignored due to the difficulties to incorporate in the framework. The Rotational Multiple Yield Surface Framework (RMYSF) is a soil volume change model developed from the standpoint of the interaction between the effective stress and shear strength. RMYSF incorporates the development of mobilised shear strength within the body of the soil whenever the soil is subjected to anisotropic compression. Currently the framework has been applied to predict the soil anisotropic stress-strain behaviour at any effective stress. This paper present the enhancement of this volume change framework using normalisation of axial strain with the understanding that the failure axial strain is not unique, but increases as the effective stress increases. This technique has essentially produced a better accuracy in the prediction of the stress-strain response for Malaysian residual soils. A series of drained tri-axial tests under various effective stresses has been conducted using specimens of 50mm diameter and 100mm height and from the stress-strain curves the inherent mobilised shear strength envelopes at various axial strains have been determined. These mobilised shear strength envelopes were then applied for the prediction of the soil stress-strain response. An excellent agreement between the predicted and the actual stress-strain curves has been achieved.

scholarly journals VOLUME CHANGE BEHAVIOUR OF BANTING CLAY BY THE CONCEPT OF EFFECTIVE STRESS AND SHEAR STRENGTH INTERACTION

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
Syahmizzi Ifwat Bin Azharnim ◽  
Mohd Jamaludin Md. Noor
Keyword(s):  
Shear Strength ◽  
Laboratory Test ◽  
Effective Stress ◽  
Volume Change ◽  
Triaxial Test ◽  
Axial Strain ◽  
Friction Angle ◽  
Stress Strain ◽  
Actual Volume ◽  
Unique Relationship

Effective stress and shear strength interaction which the stress – strain curves and mobilised shear strength envelope explained the actual volume change behaviour of the soils. The interaction that useful in prediction of stress – strain curves and unique relationship between Effective Mobilised Minimum Friction Angle and Axial Strain is important to predict the settlement at any effective stresses include the effective stress that not conducted in laboratory test. Consolidated drained triaxial test is conducted for saturated Banting CLAY and the volume change behaviour of Banting CLAY is presented from the concept of effective stress and shear strength interaction with the establishment of unique relationship between effective mobilised minimum friction angle with respect to axial strain and prediction of stress – strain curves for the saturated Banting CLAY.

scholarly journals Volume Changes and Mechanical Properties of Expansive Mudstone below Canals under Wet-Dry/Wet-Dry-Freeze-Thaw Cycles

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Rui Zhu ◽  
Ying-hao Huang ◽  
Zhu Song ◽  
Feng Zhou
Keyword(s):  
Volume Change ◽  
Northern China ◽  
Volume Measurement ◽  
Experimental Program ◽  
Failure Strength ◽  
Test Results ◽  
Compression Tests ◽  
Volume Changes ◽  
Stress Strain ◽  
Freeze Thaw

The complex environment in northern China is the main reason for degradation of expansive mudstone below the canals, which resulted in instability and damage of canal slopes. In this study, a serial of laboratory tests was conducted to explore the volume changes and mechanical behaviors of expansive mudstone below the canals in Xinjiang. The experimental program includes wet-dry (WD) and wet-dry-freeze-thaw (WDFT) tests, volume measurement, and unconfined compression tests. The test results show that during the WD cycles, the volume changes of expansive mudstones with a higher dry range would be more significant. The freeze-thaw process in the WDFT cycles resulted in a decrease of volume change ranges when the expansive mudstones had a relatively smaller dry range and a slight increase of volume change ranges when the expansive mudstones had a relatively larger dry range. In the meantime, the stress-strain relationships of expansive mudstones with different dry ranges all presented strain softening under the cycles of WD or WDFT. The first cycle resulted in a significant decrease of failure strength. After seven WD/WDFT cycles, the failure strength of expansive mudstones with different dry ranges decreased by 37.2%∼59.1%. In addition, the freeze-thaw process in the WDFT cycles promoted the softening of the stress-strain relationships and aggravated the failure strength attenuation of expansive mudstones. Through this study, we expect to provide a preliminary basis for the construction and maintenance of expansive mudstone canals in Xinjiang.

Prediction of the Effective Stress-Strain Curves of Ductile Polymer 1D-Reinforced Composites Filled with Hollow Fibers Using Parameterized Model Based on Bezier Curves

2020 ◽  
Vol 833 ◽  
pp. 93-100
Author(s):  
Alexander Pavlovich Sokolov ◽  
Vitaliy Nikolaevich Schetinin ◽  
Arseniy Sergeevich Sapelkin ◽  
Mikhail Sergeevich Kuts ◽  
Konstantin Valerievich Mikhailovskiy
Keyword(s):  
Effective Stress ◽  
Experimental Studies ◽  
Strain Curve ◽  
Ductile Material ◽  
Compression Tests ◽  
Stress Strain ◽  
Bezier Curves ◽  
Bézier Curves ◽  
Model Based ◽  
Parameterized Model

The article presents the results of numerical and experimental studies of stress-strain curves of 1D-reinforced polymer composite materials based on hollow porous fibers and epoxy matrix. The two-scale nature of the composite under research was taken into account. A surrogate easily parameterized model based on Bezier curves was developed and used to approximate the stress-strain curve of ductile material. The calculations were performed using reversible homogenization and finite element methods, which were implemented in computational subsystem of DCS GCD. Representative volume elements of the investigated materials were created using the geometry generating subsystem of DCS GCD. Test samples were made using three-axis milling machine and compression tests were carried out. Computational results of effective stress-strain curves determination were obtained and compared with experiments.

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°.

Undrained and drained (?) stress-strain response

2000 ◽  
Vol 37 (5) ◽  
pp. 1126-1130 ◽  
Author(s):  
Y P Vaid ◽  
A Eliadorani
Keyword(s):  
Effective Stress ◽  
Void Ratio ◽  
Effective Strain ◽  
Shear Stiffness ◽  
Stress Path ◽  
Stress Increment ◽  
Stress Strain ◽  
Field Problem ◽  
Deformation Response ◽  
Do So

The deformation response of saturated soils to a total stress increment at the ambient void ratio and effective stress state is shown to be dependent on the direction of the effective strain increment. It is argued that in a given field problem, most soil elements neither deform fully drained nor undrained, but do so partially drained. The degree of partial drainage controls the direction of the effective stress increment and hence the deformation response. Experimental data are presented which demonstrate how shear stiffness changes with the direction of effective stress increment as a function of the ambient effective stress state.Key words: stress-strain, undrained, drained, partially drained, stress path, stiffness.

Initiation of static liquefaction and the role of K0 consolidation

2005 ◽  
Vol 42 (3) ◽  
pp. 892-906 ◽  
Author(s):  
A B Fourie ◽  
L Tshabalala
Keyword(s):  
Effective Stress ◽  
Triaxial Compression ◽  
Stress Path ◽  
Compression Tests ◽  
Predicting Factors ◽  
Static Liquefaction ◽  
Peak Shear Stress ◽  
Material State ◽  
Undrained Loading ◽  
Gold Tailings

The potential for static liquefaction of hydraulically placed sands and silts is now well recognised. A particular category of this type of operation, tailings disposal facilities constructed using the upstream method, has come under increased scrutiny due to the large number of failures of these structures. Although the conditions that render a particular deposit susceptible to potential liquefaction are now well known, being a combination of void ratio and mean effective stress that places the material state above its steady state value, the same cannot be said about our ability to predict the stresses at which liquefaction will be initiated. The concept of a collapse surface, derived from the locus of peak shear stress values from undrained compression tests on isotropically consolidated specimens, attempts to provide a method for predicting the onset of liquefaction. As confirmed in this paper, however, application of the collapse surface concept to actual tailings dam facilities results in factors of safety based on an effective stress approach that are significantly less than unity for facilities that have not failed. On the other hand, shear strength values derived from ultimate state conditions are unconservative, predicting factors of safety significantly in excess of unity for facilities that have failed. A comparison of monotonic undrained triaxial compression tests on both isotropically- and K0-consolidated specimens of gold tailings suggests that the resolution to this dilemma lies in the recognition that a kinematic yield surface, which is a function of the consolidation stress path followed, develops in stress space. The collapse surface derived from undrained loading of K0-consolidated loose specimens is shown to provide a greatly improved capacity for predicting the onset of liquefaction under undrained loading conditions.Key words: static liquefaction, tailings, collapse surface, anisotropic.

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