Strain rate behaviour of Saint-Jean-Vianney clay

1979 ◽  
Vol 16 (1) ◽  
pp. 34-42 ◽  
Author(s):  
Y. P. Vaid ◽  
P. K. Robertson ◽  
R. G. Campanella
Keyword(s):  
Undrained Shear Strength ◽  
Shear Tests ◽  
Creep Tests ◽  
One Dimensional ◽  
Sustained Loading ◽  
Preconsolidation Pressure ◽  
Constant Rate ◽  
Rate Effects ◽  
Undrained Strength ◽  
Rate Behaviour

Rate effects on one-dimensional compressibility and undrained shear strength of a heavily overconsolidated naturally cemented clay have been studied. It is shown that in constant rate-of-strain consolidation tests the compressibility increases and the apparent preconsolidation pressure decreases with progressive decrease in rate of strain. Also a decrease in undrained strength is shown to occur with slower rates of strain in constant rate-of-strain shear and with increased time of sustained loading in creep tests. Undrained strengths from the two types of shear tests have been correlated.

Viscous–elastic–plastic modelling of one-dimensional time-dependent behaviour of clays

1989 ◽  
Vol 26 (2) ◽  
pp. 199-209 ◽  
Author(s):  
J.-H. Yin ◽  
J. Graham
Keyword(s):  
Strain Rate ◽  
Constitutive Models ◽  
Constitutive Modelling ◽  
Time Dependent ◽  
Creep Tests ◽  
Strain Rate Effects ◽  
One Dimensional ◽  
Elastic Plastic ◽  
Constant Rate ◽  
Rate Effects

Increased attention has recently been directed towards the influence of time and strain-rate effects on the behaviour of clays in one-dimensional (1-D) laboratory consolidation. The improved understanding coming from these studies must now be incorporated into improved constitutive models that can be used for analysis of foundation settlements. This paper presents a 1-D model for stepped loading using a new concept for establishing "equivalent times" during time-dependent straining. This model is then developed into a general constitutive equation for continuous loading. The model uses three parameters, λ, κ, and ψ, that can be easily found using conventional oedometer tests.The general model has been used to develop analytical solutions for creep tests, relaxation tests, constant rate of strain (CRSN) tests, and tests with constant rate of stress (CRSS). Results from three different clays have been used to examine the validity of the model. Key words: consolidation, constitutive modelling, elastic-plastic, viscous, time, creep, strain rate, relaxation.

Equivalent times and one-dimensional elastic viscoplastic modelling of time-dependent stress–strain behaviour of clays

1994 ◽  
Vol 31 (1) ◽  
pp. 42-52 ◽  
Author(s):  
Jian-Hua Yin ◽  
James Graham
Keyword(s):  
Creep Tests ◽  
One Dimensional ◽  
Compression Creep ◽  
Equivalent Time ◽  
Strain Behaviour ◽  
Preconsolidation Pressure ◽  
Constant Rate ◽  
Using Data ◽  
Strain Responses ◽  
Multistage Loading

This paper describes the recent concept of equivalent time and how it can be used in a revised version of an earlier elastic viscoplastic model for one-dimensional straining of clays. It clarifies how parameters in the model can be determined using data from single-stage or multistage creep tests. The model can describe one-dimensional stress or strain responses under general conditions that include multistage loading with creep straining, continuous loading, and unloading or reloading. It also describes modelling for constant rate of straining tests, constant rate of stressing tests, and relaxation tests. Preconsolidation pressures are shown to depend on unloading–reloading, aging, and other loading processes. Key words : clay, compression, creep, equivalent time, elastic viscoplastic, preconsolidation pressure.

scholarly journals Interpretation of vane shear tests for geotechnical stability calculations

2017 ◽  
Vol 54 (12) ◽  
pp. 1775-1780 ◽  
Author(s):  
George Kouretzis ◽  
Jubert Pineda ◽  
Kristian Krabbenhøft ◽  
Lachlan Wilson
Keyword(s):  
Effective Stress ◽  
Slip Surface ◽  
Failure Criteria ◽  
Shear Tests ◽  
Vane Shear Test ◽  
Rate Effects ◽  
Undrained Strength ◽  
Geotechnical Stability ◽  
The Given ◽  
Theoretical Considerations

In this note we consider the problem of calibrating failure criteria for short-term stability calculations based on the results of vane shear tests. Numerical and theoretical considerations supported by experimental data provide evidence that we can use the vane shear test to obtain the undrained strength of a sample tested under simple shear conditions at a normal stress equal to the horizontal effective stress at the given depth. Consequently, it is argued that there is no need to correct the field vane undrained strength to obtain the mobilized strength for embankment stability calculations, provided that soil strength is normalized to the normal effective stress acting on the slip surface and rate effects are properly considered. We further show that the standard Tresca failure criterion, albeit simplistic, will provide reasonable estimates of the mobilized strength if properly calibrated against field vane tests.

scholarly journals Laboratory and field determination of preconsolidation pressures at Gloucester

1983 ◽  
Vol 20 (3) ◽  
pp. 477-490 ◽  
Author(s):  
S. Leroueil ◽  
L. Samson ◽  
M. Bozozuk
Keyword(s):  
Test Site ◽  
Test Methods ◽  
Strain Rate Effects ◽  
Oedometer Test ◽  
Undisturbed Samples ◽  
Preconsolidation Pressure ◽  
Constant Rate ◽  
Rate Effects

In recent literature several special test methods have been proposed to measure the preconsolidation pressure of a compressible clay soil. Five methods, in addition to the conventional oedometer test, were applied to the marine clays from the Gloucester test site. The preconsolidation pressures measured using these laboratory tests were compared with that mobilized in situ below the centre of a test embankment. The investigation showed that the preconsolidation pressure is directly related to the rate of strain and that special techniques such as constant rate of strain, controlled gradient, single-stage loading, and anisotropic triaxial consolidation tend to overestimate the in-situ preconsolidation pressure. The conventional oedometer test using a load increment ratio of 0.5 and a reloading schedule of 24 h applied to good-quality undisturbed samples produced preconsolidation pressures that compared best with the in-situ values. Keywords: preconsolidation pressure, laboratory, in situ, strain rate effects, disturbance.

Profiling of overconsolidation ratio in clays by field vane

1988 ◽  
Vol 25 (1) ◽  
pp. 150-157 ◽  
Author(s):  
Paul W. Mayne ◽  
James K. Mitchell
Keyword(s):  
Shear Strength ◽  
Strain Rate ◽  
Undrained Shear Strength ◽  
Correction Factors ◽  
Test Results ◽  
Overconsolidation Ratio ◽  
Empirical Correction ◽  
Preconsolidation Pressure ◽  
Undrained Strength ◽  
Undrained Shear

The field vane (FV) has traditionally been utilized to obtain profiles of undrained shear strength in soft to medium clays. After some 40 years of experience with FV results, it has been suggested that empirical correction factors be applied to the FV data to account for the effects of strain rate, anisotropy, and disturbance on measured shear strengths. As an additional use of the device, the FV may be calibrated at each site to develop profiles of overconsolidation ratio (OCR) with depth. A data base of oedometer test results and FV strengths from 96 different clays has been compiled to use as a basis for this calibration. Key words: field vane, undrained strength, clay, overconsolidation ratio, preconsolidation pressure, shear strength, vane shear.

Numerical assessment on the performance of variable area single- and two-stage ejectors: A comparative study

2021 ◽  
pp. 095440892110331
Author(s):  
Anil Kumar ◽  
Virendra Kumar ◽  
PMV Subbarao ◽  
Surendra K Yadav ◽  
Gaurav Singhal
Keyword(s):  
Change Theory ◽  
Single Stage ◽  
Two Stage ◽  
Entrainment Ratio ◽  
Ansys Fluent ◽  
One Dimensional ◽  
Flow Parameters ◽  
Constant Rate ◽  
Numerical Assessment ◽  
The One

The two-stage ejector has been suggested to replace the single-stage ejector geometrical configuration better to utilize the discharge flow’s redundant momentum to induce secondary flow. In this study, the one-dimensional gas dynamic constant rate of momentum change theory has been utilized to model a two-stage ejector along with a single-stage ejector. The proposed theory has been utilized in the computation of geometry and flow parameters of both the ejectors. The commercial computational fluid dynamics tool ANSYS-Fluent 14.0 has been utilized to predict performance and visualize the flow. The performance in terms of entrainment ratio has been compared under on- design and off-design conditions. The result shows that the two-stage ejector configuration has improved (≈57%) entrainment capacity than the single-stage ejector under the on-design condition.

Assessing the undrained strength cross-anisotropy of three tailings types

2022 ◽  
Vol 12 (1) ◽  
pp. 1-24
Author(s):  
D. Reid ◽  
R. Fanni ◽  
A. Fourie
Keyword(s):  
Principal Stress ◽  
Stress Ratio ◽  
Additional Data ◽  
Layered Materials ◽  
Engineering Practice ◽  
Published Data ◽  
Shear Tests ◽  
Undrained Strength ◽  
Cross Anisotropy ◽  
Current Engineering

The cross-anisotropic nature of soil strength has been studied and documented for decades, including the increased propensity for cross-anisotropy in layered materials. However, current engineering practice for tailings storage facilities (TSFs) does not appear to generally include cross-anisotropy considerations in the development of shear strengths. This being despite the very common layering profile seen in subaerially-deposited tailings. To provide additional data to highlight the strength cross-anisotropy of tailings, high quality block samples from three TSFs were obtained and trimmed to enable Hollow Cylinder Torsional Shear tests to be sheared at principal stress angles of 0 and 45 degrees during undrained shearing. Consolidation procedures were carried out such that the drained rotation of principal stress angle that would precede potential undrained shear events for below-slope tailings was reasonably simulated. The results indicated the significant effects of cross-anisotropy on the undrained strength, instability stress ratio, contractive tendency and brittleness of each of the three tailings types. The magnitude of cross-anisotropy effects seen was generally consistent with previous published data on sands.

Determination of the consistency limits of soils by the fall cone test

1986 ◽  
Vol 23 (2) ◽  
pp. 241-246 ◽  
Author(s):  
Y. Wasti ◽  
M. H. Bezirci
Keyword(s):  
Shear Strength ◽  
Key Words ◽  
Water Content ◽  
Strength Criterion ◽  
Undrained Shear Strength ◽  
Wide Range ◽  
Undrained Strength ◽  
Content Range ◽  
Undrained Shear

The liquid and plastic limits for a variety of natural and artificial soils covering a wide range of plasticity, as determined by the Casagrande method and the fall cone test and based on a strength criterion, were compared. To check the validity of the strength criterion, the undrained shear strength of these soils has been determined with a laboratory vane over the water content range between these limits. A limited comparison of the undrained strength values obtained from the vane test and fall cone test is also given. Key words: Atterberg limits, consistency, fall cone, laboratory vane, shear strength.

The undrained strength of some thawed permafrost soils

1979 ◽  
Vol 16 (2) ◽  
pp. 420-427
Author(s):  
John F. Nixon ◽  
Alan J. Hanna
Keyword(s):  
Undrained Shear Strength ◽  
Soil Types ◽  
Density Range ◽  
Mackenzie Delta ◽  
Sample Depth ◽  
Wide Range ◽  
Permafrost Soils ◽  
Undrained Strength ◽  
Water Contents ◽  
Undrained Shear

A large number of undrained shear strengths have been measured for thawed, undrained permafrost samples obtained from the Niglintgak Peninsula area of the Mackenzie Delta, N.W.T. The samples are mostly deltaic silts, with a few clay tills, and cover a wide range of depths, water contents, and frozen density. The undrained shear strengths of the thawed samples have been correlated with water content, frozen density, and sample depth. For these soil types, the strength is shown to decrease to zero at frozen densities of less than about 1670 kg/m3 and at water contents greater than about 35–42%. In the Niglintgak area, the undrained shear strength of the thawed samples below a depth of 10 m becomes relatively constant in the range of 23–43 kPa. This corresponds to a frozen density range of 1780–1870 kg/m3, and previous experience with soils of this nature indicates that the corresponding thaw settlement at these depths would be less than 10%.

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