切向应力控制条件下粗粒土与结构接触面三维循环特性研究  

TEST INVESTIGATIONS ON 3D STRESS-CONTROLLED CYCLIC BEHAVIOR OF GRAVEL-STRUCTURE INTERFACE

作　　者：冯大阔[1,2] 侯文峻[3] 张建民[1,2] 

机构地区：[1]清华大学水沙科学与水利水电工程国家重点实验室,北京100084 [2]清华大学岩土工程研究所,北京100084 [3]住房和城乡建设部建筑节能与科技司,北京100835

出　　处：《岩石力学与工程学报》2011年第12期2574-2582,共9页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家重点基础研究发展计划(973)项目(2007CB714108);国家自然科学基金资助项目(50979046)

摘　　要：运用大型三维接触面试验机,对切向应力控制十字剪切、单向和往返圆形剪切路径下接触面三维循环力学特性进行直剪试验研究,并探讨剪切路径、应力幅值等因素的影响。结果表明:(1)切向应力控制循环剪切时,粗粒土与结构接触面产生明显剪切体变,且可分为可逆和不可逆两部分。(2)往返剪切路径下,随循环剪切的进行,接触面剪切体变增量经历由不可逆性剪切体变增量占优,到两者平衡,再到可逆性剪切体变占优的过程;但接触面剪切体变总体仍以不可逆性剪切体变为主。(3)接触面切向位移发生偏移,圆形路径下产生明显非共轴现象;应力幅值较小时,切向位移幅值随循环周次逐渐减小。(4)随应力幅值的增大,切向位移幅值和偏移量及单位应力切向位移增量均增大,非共轴角则减小。往返圆形路径下接触面非共轴角相邻循环符号相反,单向圆形路径下则相同,且两者数值相近。(5)圆形路径下接触面切向应力-位移曲线呈椭圆形,十字路径下则呈双曲线关系,且均随循环剪切的进行逐渐剪切硬化。剪切路径、应力幅值对接触面剪切体变、切向应力-位移关系等三维循环特性影响显著。Applied with a large-scale direct shear apparatus, the 3D stress-controlled cyclic behavior of a gravelstructure interface was investigated and the influence of the shear path and stress amplitude was discussed. The tests were performed at normal stress of 400 kPa in two-way cross, one-way and two-way circular cyclic shear paths. Results indicate that： （1） The volumetric change of interface between coarse grained soil and structure can be divided into reversible and irreversible components in two-way cyclic shear paths. （2） Irreversible increment is dominant in the first few shear cycles, and then equivalent to reversible component which finally becomes the goveming part of interface volumetric increment~ but the volumetric change of interface gives priority to irreversible component. （3） Tangential displacement migrates with shear cycles. Interface exhibits non-coaxial behavior in the tangential direction for circular shear tests; tangential displacement amplitude and increment per shear stress decrease with shear cycles when the shear stress amplitude is relatively small. （4） With the increasing shear stress amplitude, non-coaxial angle decreases and tangential displacement and tangential displacement increment per shear stress both increase. Non-coaxial angle varies little with shear cycles in one-way circular shear path, while it has opposite algebraic sign at neighboring shear cycles in two-way circular shear path. （5） Tangential stress-tangential displacement curves present an elliptical shape in circular path and hyperbolic in cross shear path Shear path and shear stress amplitude have notable influence on the 3D stress-controlled cyclic behaviors of interface.

关 键 词：土力学 接触面 粗粒土 应力控制 三维循环特性 影响因素 直剪试验 

分 类 号：TU44[建筑科学—岩土工程]