初始应力条件对松砂动力变形特性影响的试验研究

Experimental study on effect of initial stress condition on dynamic behavior and deformation parameters of loose sands

实际建筑物地基或土坡中土体在地震或波浪等复杂动力荷载作用前往往处于复杂的初始应力状态,而常规的土工动力试验通常无法再现这种复杂固结应力条件下土的动力特性。利用最新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(Dr=30%),进行了循环扭剪试验,探讨了初始主应力方向角α0和初始偏应力比η0等初始固结条件对松砂动剪切模量G和阻尼比ξ等动力变形特性的影响。

The soils under the foundation of building or within the slope are usually in complex initial stress state before subjected to cyclic loading induced by earthquake shaking or wave loading. The conventional laboratory experiments of soils cannot authentically reproduce dynamic behavior of soils under complex consolidation stress states. The soil static and dynamic universal triaxial and torsional shear apparatus recently developed in Dalian University of Technology is employed to perform experimental tests on Fujian standard sand with relative density of Dr = 30% under complex initial stress state subjected to cyclic torsional shear loading. Through a series of soil tests, the effects of both initial orientation of principal stress and the initial ratio of deviatoric stress on dynamic modulus and damping ratio of sand are investigated systematically.