运用最新研制的80 t三维多功能土工试验机,对工程中常用的粗粒土与人造粗糙钢板形成的接触面在常刚度法向边界条件切向应力控制下的动力特性进行了试验研究,并分析了切向控制方式的影响。接触面在剪切时产生了明显体变,可分为可逆和不可逆两部分;可逆性剪切体变的发展程度主要与切向位移幅值有关;不可逆性剪切体变的发展与剪切路程有很大关系;接触面体变出现了一定的异向性,且受切向加载路径、切向控制方式的影响。随着循环剪切的进行接触面切向位移发生明显偏移,其幅值也逐渐增加,受切向加载路径影响较大;切向应力、应力比、法向位移与切向位移的关系与切向加载路径、切向控制方式有很大关系。接触面在初始剪切时没有达到、随后逐渐达到抗剪强度,但破坏状态持续时间很短;其抗剪强度指标与切向控制方式关系不大。
A new apparatus is developed to investigate the stress-controlled behavior of the interface between structure and gravelly soil under constant normal stiffness condition.The test results indicate that:(1) the volumetric change is induced by cyclic shear and can be divided into reversible and irreversible parts.The reversible part is governed by tangential displacement amplitude,and the irreversible part is significantly affected by shear distance;(2) the anisotropy of interface volumetric change is obviously observed and has great concern with shear paths and control modes;(3) the tangential displacement accumulates and migrates gradually with shear cycles.The shear paths and control modes have influences on the relationship between shear stress,stress ratio,normal displacement versus tangential displacement;(4) the interface shear strength is gradually mobilized after the first few shear cycles under stress control,and its friction angle is independent of the control modes.