Simulation on Triaxial Compression Creep Deformation of Reticulate Red Clay

2011 ◽  
Vol 261-263 ◽  
pp. 1414-1418 ◽  
Author(s):  
Jian Zhong Li ◽  
Xi Qing Tang ◽  
Lu Chao Yan
Keyword(s):  
Creep Deformation ◽  
Triaxial Compression ◽  
Lake Area ◽  
Compression Tests ◽  
Creep Tests ◽  
Red Clay ◽  
Creep Stress ◽  
Compression Creep ◽  
Reticulate Red Clay ◽  
Laboratory Test Results

Triaxial compression creep tests were performed on the undisturbed specimens of reticulate red clay from Dongting Lake area (China) under different confined stress. By analyzing the laboratory test results, following conclusions were drawn: (1) creep deformation occurred in all compression tests; (2) creep deformation increases as the increasing of the creep stress (compress stress) slightly; (3) the creep deformation occurred in the triaxial compression creep tests can be well simulated with Singh-Mitchell model.

Creep Property of Reticulate Red Clay under Stepped-Load Creep Tests

2012 ◽  
Vol 446-449 ◽  
pp. 1412-1416 ◽  
Author(s):  
Jian Zhong Li ◽  
Yan Fu Cao ◽  
Ya Jun Qing
Keyword(s):  
Creep Deformation ◽  
Empirical Formula ◽  
Creep Property ◽  
Test Results ◽  
Creep Tests ◽  
Red Clay ◽  
Reticulate Red Clay ◽  
Study Test ◽  
Previous Loading

Stepped-load creep tests of undisturbed and remodeled specimens of reticulate red clay was performed in the present study. Test results and analyses of the results show that: (1) Both undisturbed and remodeled specimens showed significant creep deformation in primary loading, unloading and reloading stage, and the creep deformation of remodeled specimen is much bigger than that of undisturbed one in primary loading and reloading stage; (2) The effect of a previous loading stage on the deformation induced at a succeeding stage is significant in primary loading and reloading stage; (3) The amount of the creep deformation can be calculated accurately by an empirical formula.

scholarly journals Semi-empirical elastic–thermoviscoplastic model for clay

2016 ◽  
Vol 53 (10) ◽  
pp. 1583-1599 ◽  
Author(s):  
David Kurz ◽  
Jitendra Sharma ◽  
Marolo Alfaro ◽  
Jim Graham
Keyword(s):  
Stress Level ◽  
Axial Strain ◽  
Triaxial Compression ◽  
Compression Tests ◽  
One Dimensional ◽  
Load Duration ◽  
Compression Creep ◽  
Overconsolidated Clays ◽  
Semi Empirical ◽  
Triaxial Compression Tests

Clays exhibit creep in compression and shear. In one-dimensional compression, creep is commonly known as “secondary compression” even though it is also a significant component of deformations resulting from shear straining. It reflects viscous behaviour in clays and therefore depends on load duration, stress level, the ratio of shear stress to compression stress, strain rate, and temperature. Research described in the paper partitions strains into elastic (recoverable) and plastic (nonrecoverable) components. The plastic component includes viscous strains defined by a creep rate coefficient ψ that varies with plasticity index and temperature (T), but not with stress level or overconsolidation ratio (OCR). Earlier elastic–viscoplastic (EVP) models have been modified so that ψ = ψ(T) in a new elastic–thermoviscoplastic (ETVP) model. The paper provides a sensitivity analysis of simulated results from undrained (CIŪ) triaxial compression tests for normally consolidated and lightly overconsolidated clays. Axial strain rates range from 0.15%/day to 15%/day, and temperatures from 28 to 100 °C.

scholarly journals Relation between the Friction Angle of Sand at Triaxial Compression and Triaxial Extension and Plane Strain Conditions

Geosciences ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 29 ◽  
Author(s):  
Zenon Szypcio
Keyword(s):  
Plane Strain ◽  
Soil Mechanics ◽  
Triaxial Compression ◽  
Deformation Mode ◽  
Friction Angle ◽  
Failure Criteria ◽  
Compression Tests ◽  
Laboratory Test Results ◽  
Experimental Findings ◽  
Triaxial Extension

The strength of sand is usually characterized by the maximum value of the secant friction angle. The friction angle is a function of deformation mode, density, and stress level and is strongly correlated with dilatancy at failure. Most often, the friction angle is evaluated from results of conventional compression tests, and correlation between the friction angle of sand at triaxial compression and triaxial extension and plane strain conditions is a vital problem of soil mechanics. These correlations can be obtained from laboratory test results. The failure criteria for sand presented in literature also give the possibility of finding correlations between friction angles for different deformation modes. The general stress-dilatancy relationship obtained from the frictional state concept, with some additional assumptions, gives the possibility of finding theoretical relationships between the friction angle of sand at triaxial compression and triaxial extension and plane strain conditions. The theoretically obtained relationships presented in the paper are fully consistent with theoretical and experimental findings of soil mechanics.

Creep Property of Reticulate Red Clay under Stepped-Load Creep Tests

2012 ◽  
Vol 446-449 ◽  
pp. 1412-1416
Author(s):  
Jian Zhong Li ◽  
Yan Fu Cao ◽  
Ya Jun Qing
Keyword(s):  
Creep Property ◽  
Creep Tests ◽  
Red Clay ◽  
Reticulate Red Clay

Stress–strain–time behavior of deep sea clays

1983 ◽  
Vol 20 (3) ◽  
pp. 517-531 ◽  
Author(s):  
A. J. Silva ◽  
K. Moran ◽  
S. A. Akers
Keyword(s):  
Deep Sea ◽  
Triaxial Compression ◽  
Constant Strain Rate ◽  
Triaxial Tests ◽  
Time Behavior ◽  
Compression Tests ◽  
Creep Tests ◽  
Stress Strain ◽  
The North ◽  
Deep Sea Sediments

Summary results are presented of a comprehensive experimental study to investigate the strength, stress–strain properties, and creep behavior of fine-grained deep sea sediments. Isotropically (CIU) and anisotropically (CAU) consolidated undrained triaxial tests and drained triaxial creep tests were performed on undisturbed and reconstituted–reconsolidated (remolded) samples of smectite-rich and illite-rich deep sea clays from the North Central Pacific.The CIU Mohr–Coulomb parameters for remolded smectite [Formula: see text] were nearly identical to the undisturbed material [Formula: see text]. The parameters for remolded illite [Formula: see text] were also not significantly different than for the undisturbed material [Formula: see text].The undrained shear strength versus water content relationship (qf vs. wf) for remolded smectite is much lower than for the undisturbed material, whereas for illite the remolded strength is only slightly lower. Therefore it appears that smectite is much more sensitive than illite to the type of remolding used in these studies.The CAU tests showed that K0 agrees well with the Jaky equation, [Formula: see text]. The Mohr–Coulomb parameters were somewhat lower than the corresponding CIU results.Undisturbed and remolded samples were tested at stress levels of 10, 25, 40, and 65% of the Mohr–Coulomb strength for the determination of triaxial drained creep properties. Different relationships between stress level, strain, and time were determined for the two materials. A secondary state of creep, defined as a period of constant strain rate, was not consistently observed. Comparisons with terrestrial clays and near shore material display similar strengths of the deep sea sediments and greater deformation potential during long-term loading. Keywords: stress–strain behavior, creep, deep sea sediments, stress–strain–time behavior, triaxial compression tests.

Behavior of Cemented Reticulate Red Clay

2012 ◽  
Vol 446-449 ◽  
pp. 1666-1669 ◽  
Author(s):  
Jian Zhong Li ◽  
Li Chun Zhuo ◽  
Xi Ni
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Cement Content ◽  
Axial Strain ◽  
Test Results ◽  
Compression Tests ◽  
Red Clay ◽  
Reticulate Red Clay ◽  
Strain Deviator ◽  
Relationship Of

Mechanical properties of cemented reticulate red clay were studied in present research. Test results show that: (1) shear strength of cemented reticulate red clay increase exponentially as the increasing of cement content; (2) shear strength of cemented reticulate red clay decrease polynomially as the increasing of water content; (3) mechanical properties of cemented reticulate red clay affected significantly by curing time and curing confined pressure. In order to study viscous properties of cemented reticulate red clay, cemented reticulate red clay specimens were compressed in triaxial chamber at different shear rate. Results of the compression tests show that it is obvious that the axial strain-deviator stress relationship of cemented reticulate red clay affects by the strain rate.

Thermodynamic Properties of Soft Sedimentary Rock in Geotechnical Engineering

2012 ◽  
Vol 170-173 ◽  
pp. 687-691 ◽  
Author(s):  
Jing Yin Wang ◽  
Fang Liu
Keyword(s):  
Thermodynamic Properties ◽  
Sedimentary Rock ◽  
Geotechnical Engineering ◽  
Triaxial Compression ◽  
Soft Rock ◽  
Compression Tests ◽  
Creep Tests ◽  
Oil Drilling ◽  
Viscoplastic Model ◽  
Conventional Triaxial Compression

In geotechnical engineering such as supporting of deep and soft rock roadway ,oil drilling , and construction of military underground defensive facility, thermodynamic properties of soft sedimentary rock has guiding significances .The study of the thermal constitutive behavior of rock under temperature has been done for many years, and many achievement have been got on this issue. In this paper, some experimental researches on the thermo-mechanical characteristics of soft sedimentary rock have been presented. Some test results have been simulated with a thermo-elasto-viscoplastic model. The results show that the proposed thermo-elasto-viscoplastic model reflects the visco-elastoplastic properties of rock，and can describe the thermo-mechanical behaviors of soft shale rocks in not only drained conventional triaxial compression tests but also drained triaxial creep tests. So it can be used for analysis of theology and stability of rock engineering.

Micro-Nano Fine Characterization of Coal Fracture Evolution During the Triaxial Compression Creep

2021 ◽  
Vol 21 (1) ◽  
pp. 495-504
Author(s):  
Weidong Lu ◽  
Guoying Wei ◽  
Zehua Wang ◽  
Tianrang Jia ◽  
Shaodong Sun ◽  
...  
Keyword(s):  
Gas Flow ◽  
Axial Stress ◽  
Triaxial Compression ◽  
Ct Scanning ◽  
Flow Rule ◽  
Loading Conditions ◽  
Creep Tests ◽  
Fracture Evolution ◽  
Compression Creep ◽  
Binary Image Processing

The production and evolution of fractures during coal creep will directly affect the occurrence, extraction and flow law of gas in a coal seam. The coal fracture evolution under creep conditions was studied by qualitative analysis and quantitative characterization. At a room temperature of 24 °C, triaxial compression creep tests of coal samples from the Zhaogu No. 2 coal mine in Jiaozuo were carried out under different loading conditions (0 MPa, 6 MPa, 9 MPa and 12 MPa), and low field nuclear magnetic resonance technique tests and industrial CT scanning experiments were performed. The obtained CT images were analyzed with the MATLAB software for equalization and binary image processing. The development and distribution of fractures in coal samples under different loading conditions were studied. The results show that the internal fractures are unevenly distributed and controlled by the main fracture, and the expansion direction of fractures is parallel to the direction of the maximum effective compressive stress. The number of fractures shows an increasing trend with the increase of axial stress, and the pace of growth of new fractures accelerates. The primary fractures in the coal body expand and generate new fractures, which improves the connectivity of the fractures in the coal body. The research results can provide a basis for studying the gas flow rule around the borehole and determining the influence range of the borehole.

scholarly journals Study on the Estimation of Rock Rheological Parameters under Multi-level Loading and Unloading Conditions

2018 ◽  
Vol 213 ◽  
pp. 02003
Author(s):  
Bing Han ◽  
Qiang Fu
Keyword(s):  
Triaxial Compression ◽  
Constitutive Models ◽  
Viscosity Coefficient ◽  
Rheological Parameters ◽  
Creep Tests ◽  
Compression Creep ◽  
Study Results ◽  
Rock Creep ◽  
Multi Level ◽  
Level Loading

Determining reasonable rheological constitutive models based on laboratory rock creep test data and estimating rheological parameters are important means of studying rheological mechanical property of rocks. Previous rock uniaxial or triaxial compression creep tests mostly adopted the method of multi-level loading. In order to study the influence of unloading stress on the estimation of rock rheological parameters, rock triaxial creep tester RLW-2000 was used in this paper to carry out triaxial compression creep tests for granites in a given area with two different stress paths of multi-level loading and stepwise unloading. Study results indicate that rock rheological parameters obtained vary with different stress paths. The instantaneous elastic modulus and viscosity coefficient obtained through loading show a stepwise increase, while the viscoelastic modulus shows a progressive decrease.

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