Effects of axial cyclic loading at constant confining pressures on deformational characteristics of anisotropic argillite
来源期刊：中南大学学报(英文版)2013年第3期
论文作者：ZHANG Jiu-chang(张久长) ZHOU Su-hua(周苏华) FANG Li-gang(方理刚) XU Xiang-hua(许湘华)
文章页码：799 - 811
Key words：anisotropic argillite; coupled elasto-plasticity; cyclic loading tests; elastic parameters; plastic strain
Abstract: Triaxial cyclic loading tests have been performed to assess the influence of plastic deformation on inelastic deformational properties of anisotropic argillite with bedding planes which is regarded as a kind of transversely isotropic media. Considering argillite’s anisotropy and inelastic deformational properties, theoretical formulae for calculating oriented elastic parameters were deduced by the unloading curves, which can be better fitted for the description of its elasticity than loading curves. Test results indicate that with the growth of accumulated plastic, strain, the apparent elastic modulus of argillite decreases in a form of exponential decay function, whereas the apparent Poisson ratio increase in a form of power equation. A ratio of unloading recoverable strain to the total strain increment occurred during a loading cycle is defined to illustrate the characteristic relations between anisotropic coupled elasto-plastic deformation and plastic strain. It is significant to observe that high stress level and plastic history have an inhibiting effect on argillite anisotropy.
ZHANG Jiu-chang(张久长)1, ZHOU Su-hua(周苏华)2, FANG Li-gang(方理刚)2, XU Xiang-hua(许湘华)3
(1. Institute of Geotechnical Engineering, Hohai University, Nanjing 210098, China;
2. School of Civil Engineering, Central South University, Changsha 410075, China;
3. Guizhou Provincial Department of Transportation, Guiyang 550003, China)
Abstract:Triaxial cyclic loading tests have been performed to assess the influence of plastic deformation on inelastic deformational properties of anisotropic argillite with bedding planes which is regarded as a kind of transversely isotropic media. Considering argillite’s anisotropy and inelastic deformational properties, theoretical formulae for calculating oriented elastic parameters were deduced by the unloading curves, which can be better fitted for the description of its elasticity than loading curves. Test results indicate that with the growth of accumulated plastic, strain, the apparent elastic modulus of argillite decreases in a form of exponential decay function, whereas the apparent Poisson ratio increase in a form of power equation. A ratio of unloading recoverable strain to the total strain increment occurred during a loading cycle is defined to illustrate the characteristic relations between anisotropic coupled elasto-plastic deformation and plastic strain. It is significant to observe that high stress level and plastic history have an inhibiting effect on argillite anisotropy.
Key words:anisotropic argillite; coupled elasto-plasticity; cyclic loading tests; elastic parameters; plastic strain
