循环荷载作用下粗粒土与结构接触面变形特性的试验研究

Experimental study on cyclic behavior of interface between soil and structure

使用新研制的大型土与结构接触面循环加载剪切仪,对粗粒土与结构接触面在循环荷载作用下的力学特性进行了系统的试验研究,从宏观和细观两个层次进行了分析测量,讨论了循环荷载作用下接触面受力变形的规律和机理。试验表明,在循环荷载作用下,粗粒土与结构接触面的相对法向位移总体上表现为单调增长,但在一个剪切循环内表现出有规律的增减变化,因此接触面的剪胀体变可以划分为可逆性和不可逆性两个分量。接触面表现出由于初次剪切造成的细观结构异向性导致的宏观结构异向性。剪切过程中接触面存在着土颗粒破碎和剪切压密两种物态变化机制,共同支配着接触面力学性质的变化。

A series of cyclic shear tests was performed to study the cyclic behavior as well as mechanism of interface between coarse-grained soil and structure with a new multifunction apparatus through both macro-and micro-approaches. It was shown that the normal displacement of the interface cumulated with the increase of shear cycles and varied periodically in a single cycle. Furthermore, aeolotropy of interface was discovered experimentally and theoretically. When the interface was cyclically sheared, two physical states, including crushing and compression of soil near the structure surface, governed the mechanical response of the interface.