地震作用下盐水沟隧道破坏成因研究  

Failure Mechanism of Yanshuigou Tunnel under Earthquake Action

作　　者：赵晓勇[1] 杨长卫[1] 张建经[1] 

机构地区：[1]西南交通大学交通隧道工程教育部重点实验室,四川成都610031

出　　处：《中国铁道科学》2015年第5期61-67,共7页China Railway Science

基　　金：国家"九七三"计划项目(2011CB013605);国家自然科学青年基金资助项目(51408510)

摘　　要：针对2009年库车县地震过后盐水沟隧道产生的震害现象,通过现场调查、386组围岩的动三轴试验、理论推导及数值分析,研究隧道衬砌开裂破坏的成因。现场调查结果表明,衬砌中产生的各种裂缝以交叉裂缝为主,其次是斜向裂缝、纵向裂缝和地面裂缝,并且裂缝数量的分布在地形的起伏较大地段和围岩变化段比较密集,洞口段破坏最为严重。数值分析和室内试验结果表明:低频地震波、起伏较大的地形地貌、隧道内围岩等级的差异以及地震过程中围岩动力特性的变化是造成盐水沟隧道衬砌发生破坏的主要原因;随着输入地震波频率与隧道自振频率之间的差异逐渐增大,隧道衬砌的变形逐渐减小且向刚体位移发展;隧道拱顶的竖向位移、加速度等地震响应与围岩等级呈负相关关系;随围岩动剪切应变的增加,围岩的动剪切模量比减小,动阻尼比增大;埋深在2 H^5 H(H为隧道高度)时,隧道衬砌的变形较大,埋深在5 H^30 H时,衬砌变形随着隧道埋深的增加而迅速降低,大于30 H时,衬砌变形趋于平缓。Seismic damage occurred in Yanshuigou tunnel after the earthquake in Kuche in 2009. The failure mechanism of the cracking in tunnel lining was studied by field investigation, the dynamic triaxial tests of 386 groups of surrounding rock, theoretical derivation and numerical analysis. The results of field investigation show that the crossed cracks are dominant in various cracks of lining, then in succession are inclined cracks, longitudinal cracks and ground cracks. The distribution of crack numbers is comparatively dense on the section of much fluctuated terrain and the change section of surrounding rock. The failure of the portal section is the most serious. The results of numerical analysis and laboratory tests show that the low frequency seismic wave, much fluctuated terrain, the difference in the levels of the surrounding rock and the change of dynamic characteristics during earthquake are the main reasons for the failure in the lining of Yanshuigou tunnel. The deformation of tunnel lining decreases gradually and towards rigid displacement with the increase of the difference between the frequency of input seismic wave and the natural frequency of tunnel. The seismic responses of the vertical displacement and acceleration of tunnel vault is in negative correlation with the level of surrounding rock. With the increase of the dynamic shear strain of surrounding rock, the dynamic shear modulus ratio decreases and the dynamic damping ratio increases. When the buried depth is 2H-5H （H stands for the height of tunnel）, the deformation of tunnel lining is larger. When the buried depth is 5H-30H, the deformation of tunnel lining decreases rapidly with the increase of buried depth. When the buried depth is greater than 30H, the deformation of tunnel lining tends to be stable.

关 键 词：隧道 地震响应 初砌 围岩 裂缝 变形 破坏成因 

分 类 号：U451.4[建筑科学—桥梁与隧道工程]