Experimental Research on Dynamic Poisson’s Ratio of Silty Clay

2010 ◽  
Vol 168-170 ◽  
pp. 286-292
Author(s):  
Hua Pan ◽  
Guo Xing Chen ◽  
Tian Sun
Keyword(s):  
Shear Strain ◽  
Poisson’S Ratio ◽  
Stress Ratio ◽  
Confining Pressure ◽  
Poisson's Ratio ◽  
Cyclic Loads ◽  
Silty Clay ◽  
Shear Tests ◽  
Torsional Shear ◽  
Hollow Cylinder Apparatus

Cyclic triaxial and cyclic torsional shear tests were performed on undisturbed marine silty clay by the hollow cylinder apparatus, and the Young’s modulus and shear modulus were obtained respectively. Furthermore, the influence of effective confining pressure and stress ratio on dynamic Poisson’s ratio was investigated on this basis. It was found that the dynamic Poisson’s ratio increases with generalized shear strain, but decreases with increasing effective confining pressure and stress ratio. The effect of effective confining pressure and stress ratio on dynamic Poisson’s ratio was weakened as the generalized shear strain was increasing. The dynamic Poisson’s ratio was about 0.48 when the Poisson’s ratio was increased to 1.8E-2 or so, and the test was terminated. There was no shear dilatation during all tests because the Poisson’s ratios were smaller than 0.5. It indicates that the marine silty clay tested in this paper has a good stability under cyclic loads.

scholarly journals Experimental Research on Deformation Characteristics of Using Silty Clay Modified Oil Shale Ash and Fly Ash as the Subgrade Material after Freeze-Thaw Cycles

2019 ◽  
Vol 11 (18) ◽  
pp. 5141 ◽  
Author(s):  
Wei ◽  
Li ◽  
Han ◽  
Han ◽  
Wang ◽  
...  
Keyword(s):  
Plastic Strain ◽  
Stress Ratio ◽  
Dynamic Stress ◽  
Confining Pressure ◽  
Silty Clay ◽  
Loading Frequency ◽  
Axial Deformation ◽  
Cumulative Strain ◽  
Cumulative Plastic Strain ◽  
Shale Ash

To achieve the purposes of disposing industry solid wastes and enhancing the sustainability of subgrade life-cycle service performance in seasonally frozen regions compared to previous research of modified silty clay (MSC) composed of oil shale ash (OSA), fly ash (FA), and silty clay (SC), we identified for the first time the axial deformation characteristics of MSC with different levels of cycle load number, dynamic stress ratio, confining pressure, loading frequency, and F-T cycles; and corresponding to the above conditions, the normalized and logarithmic models on the plastic cumulative strain prediction of MSC are established. For the effect of cycle load number, results show that the cumulative plastic strain of MSC after 1, 10, and 100 cycle loads occupies for 28.72%~35.31%, 49.86%~55.59%, and 70.87%~78.39% of those after 8000 cycle loads, indicating that MSC possesses remarkable plastic stability after 100 cycles of cycle loads. For the effect of dynamic stress ratio, confining pressure, loading frequency, and F-T cycles, results show that dynamic stress ratio and F-T cycles are important factors affecting the axial deformation of MSC after repeated cycle loads; and under the low dynamic stress ratio, increasing confining pressure and loading frequency have insignificant effect on the axial strain of MSC after 8000 loads. In term of the normalized and logarithmic models on the plastic cumulative strain prediction of MSC, they have a high correlation coefficient with testing data, and according to the above models, the predicted result shows that the cumulative plastic strain of MSC ranges from 0.38 cm to 2.71 cm, and these predicted values are within the requirements in the related standards of highway subgrades and railway, indicating that the cumulative plastic strain of MSC is small and MSC is suitable to be used as the subgrade materials.

Liquefaction assessment by the unit energy concept through centrifuge and torsional shear tests

2007 ◽  
Vol 44 (11) ◽  
pp. 1286-1297 ◽  
Author(s):  
Hesham M. Dief ◽  
J. Ludwig Figueroa
Keyword(s):  
Unit Volume ◽  
Site Response ◽  
Confining Pressure ◽  
Cohesionless Soils ◽  
Shear Tests ◽  
Liquefaction Susceptibility ◽  
Torsional Shear ◽  
Energy Concept ◽  
Unit Energy ◽  
Different Grain Size

The fundamentals of the energy concept to assess the liquefaction potential of cohesionless soils have been formulated in recent years. To examine the validity of this procedure, a series of centrifuge liquefaction tests were carried out using the same soils that were tested previously as part of extensive research conducted on the subject at Case Western Reserve University. A total of 30 liquefaction tests at accelerations of 50g and 60g  were conducted on scaled pore fluid saturated models, prepared in a laminar box, representing a prototype soil deposit. The influence of relative density and effective confining pressure, as well as the effect of different grain size distribution on the energy per unit volume required for liquefaction, is studied. Generalized relationships were obtained by performing regression analyses between the energy per unit volume at the onset of liquefaction and liquefaction affecting parameters. These equations are compared with similar ones that were developed previously using torsional shear tests. A rational procedure to determine site response to earthquake loading and liquefaction susceptibility of a soil deposit is verified.

Experimental Study on Dynamic Poisson’s Ratio of Rock-Fill Materials under Cyclic Loadings

2011 ◽  
Vol 243-249 ◽  
pp. 2443-2450
Author(s):  
De Gao Zou ◽  
Jing Mao Liu ◽  
Bin Xu ◽  
Xian Jing Kong ◽  
Tao Gong
Keyword(s):  
Shear Modulus ◽  
Shear Strain ◽  
Poisson’S Ratio ◽  
Dynamic Properties ◽  
Dynamic Responses ◽  
Poisson's Ratio ◽  
Dynamic Shear Modulus ◽  
Empirical Formulas ◽  
Rock Fill ◽  
Fill Materials

Dynamic Poisson’s ratio is a very important parameter for the numerical analysis of dynamic responses in a rock-fill dam. It is generally taken as a constant of which the significance is generally underrated. In order to have a better understanding of the dynamic properties of rock-fill materials, a series of tests were performed to investigate the effects of the shear strain on the dynamic Poisson’s ratio. The experimental results show that dynamic Poisson’s ratio varies with the shear strain, the dynamic shear modulus and the confining pressure. In addition, the empirical formulas to determine the dynamic Poisson’s ratio with the shear strain or normalized shear modulus are given in this paper.

scholarly journals Pore water pressure responses of saturated sand and clay under undrained cyclic shearing

2021 ◽  
Author(s):  
An ◽  
Hiroshi ◽  
Nhan ◽  
Nhan ◽  
Tien ◽  
...  
Keyword(s):  
Shear Strain ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Silty Clay ◽  
Shear Tests ◽  
Sand Liquefaction ◽  
Cyclic Shear ◽  
Wide Range ◽  
Number Of Cycles

In this study, changes in the pore water pressure were observed for saturated specimens of a loose fined-grain sand (Nam O sand) and a soft silty clay (Hue clay) subjected to undrained cyclic shearing with different testing conditions. The cyclic shear tests were run for relatively wide range of shear strain amplitude (g = 0.05%-2%), different cycle numbers (n = 10, 50, 150 and 200) and various shear directions (uni-direction and two-direction with phase difference of q = 0o, 45o and 90o). It is indicated from the experimental results that under the same cyclic shearing condition, the pore water pressure accumulation in Hue clay is at a slower rate, suggesting a higher cyclic shear resistance of Hue clay than that of Nam O sand. Liquefaction is reached easily in nominally 50% relative density specimens of Nam O sand when g ³ 0.4%, meanwhile soft specimen of Hue clay is not liquefied regardless of the cyclic shearing conditions used in this study. The threshold number of cycles for the pore water pressure generation generally decreases with g meanwhile, the threshold cumulative shear strain for such a property mostly approaches 0.1%. In addition, by using this new strain path parameter, it becomes more advantageous when evaluating the pore water pressure accumulation in Nam O sand and Hue clay subjected to undrained uni-directional and two-directional cyclic shears.

scholarly journals The Research on Strength and Deformation Behaviors of Buffer/Backfill Material under High-Temperature and High-Pressure Conditions

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Hao Chen ◽  
Hai-Bo Lv ◽  
Zheng-han Chen ◽  
Yu-han Li
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Water Content ◽  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Confining Pressure ◽  
Poisson's Ratio ◽  
Dry Density ◽  
Gmz Bentonite

By using the high-temperature and high-pressure triaxial apparatus, 81 undrained triaxial shearing tests of GMZ bentonite were carried out, and the effects of temperature, confining pressure, water content, and dry density on the deformation and strength characteristics of GMZ bentonite were systematically analyzed. Five results are presented in this paper: (1) confining pressure and dry density have a great influence on the failure forms of GMZ bentonite; under the nonconfined pressure condition, the failure forms of the specimen are brittle failure, and it is the same with high dry density, but the specimens with low dry density and high confining pressure exhibit plastic failure; (2) the strength of GMZ bentonite decreases with increasing water content; the position of the deviator stress-axial strain curve under low dry density rises with the increase of temperature, whereas the location of the curve under high dry density decreases with the rise of temperature; (3) initial Young’s modulus rises with increasing temperature under low dry density, but it is on the contrary under high dry density; with rising water content, initial Young’s modulus generally decreases; (4) Poisson’s ratio rises with rising temperature. The effect of dry density and water content on Poisson’s ratio is insignificant; and (5) the formulae of cohesion and internal friction angle of GMZ bentonite with the changing dry density, water content, and temperature are proposed, respectively. The research results of this paper provide a scientific basis for analyzing the thermo-hydro-mechanical coupling characteristics of buffer materials.

Influence of Shear Strain on the Poisson’s Ratio of Clean Sands

2016 ◽  
Vol 34 (5) ◽  
pp. 1359-1373 ◽  
Author(s):  
Troyee Tanu Dutta ◽  
Sireesh Saride
Keyword(s):  
Shear Strain ◽  
Poisson’S Ratio ◽  
Poisson's Ratio
Sign in / Sign up

Export Citation Format

Share Document