静力与动力组合应力条件下饱和松砂变形特性的试验研究

利用大连理工大学新引进与研制开发的土工静力-动力液压三轴-扭转多功能剪切仪,针对福建标准砂,在相对密度为Dr=3 0 %的松散状态下,在不同的三向非均等固结应力状态下进行了应力控制式循环扭剪试验和竖向-扭转耦合剪切试验,通过对比试验结果着重探讨了初始固结主应力方向与循环应力变化模式对饱和松砂动应力-应变关系特性的影响,并采用相对有效应力比峰值与广义剪应变作为参变量对应力-应变模式进行了探讨。试验结果表明,相对有效应力比峰值与广义剪应变之间符合良好的双曲线关系,初始固结主应力方向对砂土的应力-应变关系特性具有不容忽视的影响。

AN EXPERIMENTAL STUDY ON THE DEFORMATION CHARACTERISTICS OF SATURATED LOOSE SAND UNDER COUPLED STATIC AND DYNAMIC COMBINED STRESS CONDITIONS

In this paper,a new apparatus for static and dynamic un iver sal triaxial and torsional shear soil testing is employed to perform stress-con trolled cyclic torsional shear tests and coupled vertical and torsional shear te sts under different three-dimensional initial anisotropic consolidation stress conditions.Through a series of experimental tests on the Fujian standard sand wi th a relative density of D r=30%,the effects of the initial orientations of the principal stresses on dynamic deformation behavior are examined.It is shown based on comparative studies,that the initial orientation of the principal stre ss has an appreciable influence on the dynamic stress-strain characteristics of saturated loose sand.Furthermore,it is found that the relative peak effective s tress ratio is a representative parameter that can authentically reproduce the c ombined effects of the initial stress condition and the cyclic shear stress amp litude,and that the relationship between the peak ratio of relative effective d eviatoric stress and the generalized deviatoric strain can be represented by an empirical hyperbolic model,and the related parameters experimentally defined ar e dependent on the initial stress conditions.