多工况下墙-砂土界面剪切试验装置研发与试验规律研究  

Research on Device Development and Test Law of Shear Test for Wall-Sand Interface under Multiple Working Conditions

作　　者：曹海莹[1,2] 张书恒 武崇福[2] CAO Haiying;ZHANG Shuheng;WU Chongfu(Key Lab of Green Construction and Intelligent Maintenance for Civil Engineering of Hebei Province,Yanshan University,Qinhuangdao Hebei 066004,China;School of Civil Engineering and Mechanics,Yanshan University,Qinhuangdao Hebei 066004,China)

机构地区：[1]燕山大学河北省土木工程绿色建造与智能运维重点试验室,河北秦皇岛066004 [2]燕山大学建筑工程与力学学院,河北秦皇岛066004

出　　处：《中国铁道科学》2023年第2期11-23,共13页China Railway Science

基　　金：国家自然科学基金资助项目(51308486);河北省自然科学基金项目(E2020203168,E2020203075);河北省高等学校科学技术研究重点项目(ZD2020330)。

摘　　要：铁路工程中深基坑稳定性对于铁路安全有着重要影响,而其中的关键问题是挡墙结构与土体的相互作用。为进一步揭示不同工况下混凝土挡墙-砂土界面相互作用机制,设计研发多功能界面剪切试验装置并开展墙-砂土界面剪切试验,依据墙-砂土摩擦角变化特征提出“双预警域”基坑稳定性判断方法。结果表明:混凝土挡墙-砂土界面的剪应力-剪切位移曲线呈现显著的非线性变化特征,竖向应力相同时,挡墙粗糙度越大,峰值剪应力越大;主动土压力状态时,不同转动模式下的界面抗剪强度随转动参量增加而先增后减、再趋于平稳,被动土压力状态时则先增后趋于平稳;挡墙粗糙度为I级时,主动土压力状态时绕墙顶转动模式下的抗剪强度最大,而在被动土压力状态时绕墙底转动模式下的抗剪强度最大,且挡墙粗糙度越大,转动模式对抗剪强度的影响越小。基于多工况下墙土界面剪切试验所得界面摩擦角变化规律的“双预警域”基坑稳定性判断方法,可有效提高基坑稳定状态判断的准确性。The stability of deep foundation pit in railway engineering has an important influence on railway safety,in which the key problem is the interaction between retaining wall structure and soil.In order to further reveal the interaction mechanism of concrete retaining wall-sand interface under different working conditions,a multi-functional interface shear test device was designed and developed to carry out the shear test of wall-sand interface.According to the variation characteristics of wall-sand friction angle,a“double early warning domains”method for judging the stability of foundation pit was proposed.The results show that the shear stress-shear displacement curves of concrete retaining wall-sand interface present significant nonlinear variation characteristics.When the vertical stress is the same,the greater the roughness of the retaining wall,the greater the peak shear stress.Under different rotation modes in the active earth pressure state,the interfacial shear strength increases first,then decreases,and then tends to be stable with the increase of rotation parameters,while in the passive earth pressure state,it increases first and then tends to be stable.When the roughness of the retaining wall is Grade I,the shear strength under the rotation mode around the top of the wall is the largest in the active earth pressure state,while the shear strength under the rotation mode around the bottom of the wall is the largest in the passive earth pressure state.And the greater the roughness of the retaining wall,the smaller the impact of the rotation mode on shear strength.Based on the variation law of the interface friction angle obtained from the wall-soil interface shear test under multiple working conditions,the“double early warning domains”method for judging the stability of foundation pit can effectively improve the judgment accuracy of its stable state.

关 键 词：铁路工程 深基坑 墙-砂土界面 剪切试验 粗糙度 转动模式 双预警域 

分 类 号：U443.22[建筑科学—桥梁与隧道工程] TU476.4[交通运输工程—道路与铁道工程]