摘要
泡沫混凝土作为隧道减震材料在抵抗地震压剪荷载方面具有重要作用,为了研究减震层-衬砌接触面在地震压剪荷载作用下的破坏特征与剪应力演化规律,利用RMT-150C电液伺服试验机开展了二者接触面在不同法向应力下的直剪试验,获得了剪应力-剪切位移、峰值强度、残余强度、剪切刚度的变化规律及接触面的破坏特征和物态变化。根据有限元模拟结果,探究接触面上剪应力的分布及演化规律。研究表明:泡沫混凝土-衬砌接触面的破坏特征受法向应力与泡沫混凝土密度共同影响,其剪应力-剪切位移曲线形态可归结为3种类型,且随泡沫混凝土密度和法向应力的变化可以相互转化;泡沫混凝土密度及法向应力对接触面峰值强度、残余强度及剪切刚度的影响是相互的,且法向应力的影响权重较大。根据剪应力-剪切位移曲线的变化规律,提出了复合指数模型来反映泡沫混凝土-衬砌接触面在压剪作用下损伤演化及摩擦滑移过程,研究结果可以为更加有效的抗减震设计提供一定参考。
The foam concrete serving as a tunnel damping material plays an important role in resisting seismic compression-shear load. This study aims to investigate failure characteristics and shear stress evolution law of the contact surface between the lining and shock absorption layer under seismic loads. Thus, direct shear tests are carried out under different normal stress levels by using RMT-150 C electro-hydraulic servo testing machine. We obtain the variations of shear stress-shear displacement curves, peak strength, residual strength, shear stiffness as well as the failure characteristics and physical state changes of the contact surface through tests. Meanwhile, according to the FEM simulation results, the distribution and evolution laws of shear stress in contact surface are studied. The results show that the failure characteristics of the contact surface between the lining and foam concrete are affected by the normal stress and the density of foam concrete. In addition, shear stress-shear displacement curves are divided into three types which could be converted to each other with the changes in foam concrete density and the normal stress. The influences of the foam concrete density and normal stress on the peak strength, residual strength and shear stiffness of the contact surface are mutual, and the influence of normal stress weights higher. Finally, according to the variation of shear stress-shear displacement curves, the composite index model is proposed to reflect the damage evolution and friction-slip process of the contact surface between the foam concrete and lining under the compressive-shear load. Therefore, this study can provide certain references for the effective aseismic design.
作者
赵坤
陈卫忠
赵武胜
杨典森
宋万鹏
李灿
马少森
ZHAO Kun;CHEN Wei-zhong;ZHAO Wu-sheng;YANG Dian-senl;SONG Wan-peng;LI Can;MA Shao-sen(State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, Hubei 430071, China;University of Chinese Academy of Sciences, Beijing 100049, China;Geotechnical and Structural Engineering Research Center, Shandong University, Jinan, Shandong 250061, China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2018年第7期2662-2670,共9页
Rock and Soil Mechanics
基金
国家重点基础研究发展计划(973计划)(No.2015CB057906)
国家杰出青年科学基金(No.51225902)
国家自然科学青年基金(No.51409245)~~
关键词
接触面
直剪试验
数值模拟
泡沫混凝土
复合指数模型
contact surface
direct shear test
numerical simulation
foam concrete
composite index model
