高水压下衬砌背后空洞对结构受力的影响  

Influence of voids behind lining on mechanical behavior of the tunnel lining structure under a high water pressure

作　　者：徐晨[1] 邓如勇 崔戈[1] 方勇[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：《水文地质工程地质》2016年第3期44-51,共8页Hydrogeology & Engineering Geology

基　　金：国家自然科学基金项目资助(51278422);国家科技支撑计划课题资助(2012BAG05B03);四川省青年科技基金项目资助(2012JQ0021)

摘　　要：岩溶区隧道衬砌背后空洞与高透水压力的共同作用,改变了衬砌的受力状态,导致结构原本良好的受力状况恶化,进而可能造成衬砌的开裂破损。采用FLAC3D软件研究不同空洞位置对应力场分布、渗流场分布、二次衬砌内力的影响以及在高透水压力下拱顶空洞大小对二衬内力的影响规律。结果表明:竖直应力场为主应力场时空洞周边会出现应力增大区和应力减小区;空洞会使3倍空洞直径范围内外水压力明显折减;无外水压力时空洞对二次衬砌弯矩的影响远大于轴力;无论空洞存在与否,存在何位置,各测点内力均随水头高度的升高呈现线性变化,拱底与拱脚内力大小及变化速率都远大于其他测点,且空洞不同位置下内力随水压的变化速率有很大区别;边墙空洞使衬砌结构处于偏压状态,且随水头高度的升高偏压效应更加明显;拱部弯矩随拱顶空洞大小线性特征明显。Under the interaction of voids behind the tunnel lining and the high permeable water pressure,the state of the tunnel lining forces in Karst areas is usually changed,which may lead to a bad tunnel lining forces state,and even cause cracking damage. This study was carried out relying on the FLAC3 D,which examines the effect of voids position on the stress field,seepage field and the mechanical behavior of the tunnel lining,and the influence law of internal force with a high permeable external water pressure when the voids is behind arch with different sizes. The results show that when the vertical stress field is the principal stress field,decrease and increase stress fields will appear in the surrounding void. The void can make the external water pressure obvious reduction within the range of three times the hole diameter distance. The influence of voids on bending moment of the secondary lining is greater than the axial force when there is no water pressure. No matter the void exists or not and no matter where the void exists,the internal force of lining is increased linearly. With the increasing water pressure,both the value and change rate of the internal force in the arch spring and invert are larger than those of other measuring points,and the change rate is different with voids in different positions. The void behind the side wall will make the lining structure under the bias state,and the higher the waterhead,the more obvious the bias effect. The bending moment increases linearly with the increasing arch hole size.

关 键 词：背后空洞 外水压 隧道衬砌 内力特性 数值模拟 

分 类 号：U456.3[建筑科学—桥梁与隧道工程]