考虑孔隙水压力效应和非线性破坏准则的浅埋地下洞室支护力上限分析  

Upper bound solutions of supporting pressure of shallow cavities subjected to pore water pressure based on nonlinear failure criterion

作　　者：黄阜[1] 杨小礼[1] 黄戡[1] 张道兵[1] 

机构地区：[1]中南大学土木工程学院,湖南长沙410075

出　　处：《岩土工程学报》2011年第12期1903-1909,共7页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(51178468);湖南省杰出青年基金(09JJ1008);湖南省研究生科研创新项目(CX2009B043)

摘　　要：由于孔隙水压力的作用,位于饱和土体中地下结构的力学和变形特征与完全干燥土体中的结构有很大不同。根据浅埋地下洞室的非线性破坏特征构建了一个新的曲线形破坏机制,并将孔隙水压力做的功率作为一个外力功率引入极限分析上限定理的虚功率方程中,推导了孔隙水压力作用下饱和土体中浅埋洞室支护力和速度间断线上限解的解析表达式。利用变分原理,对此支护力的上限解进行了优化计算,得到了支护力的最优上限解,并对单一影响参数变化下的支护力随埋深变化规律和洞室顶部塌落面的形状进行了研究。研究结果表明:孔隙水压力对饱和土体中浅埋洞室的支护力和塌落面均有重大影响;支护力和塌落面都随孔隙水压力系数的增大而增大。Due to the effect of pore water pressure,the mechnical and deformation characteristics of underground structures located in saturated soils are different from those located in completely dry soils.According to the nonlinear failure characteristics of shallow cavities,a new curved failure mechanism is constructed.By regarding the work rate of pore water pressure as an external loading work rate,the effect of pore water pressure is introduced into the virtual work rate equation of the upper bound theorem,and the upper solution expressions of supporting pressure and detaching curve of the shallow cavities subjected to pore water pressure are derived.By using variational calculation to optimize the objective function,the optimal upper solutions of supporting pressure and collapsing block shape of shallow cavity are obtained.According to the results of parametric analysis,the pore water pressure has significant influence on the supporting pressure and collapsing surface of the shallow cavities.Furthermore,both the supporting pressure and collapsing surface increase with the increase of pore water pressure coefficient.

关 键 词：孔隙水压力 非线性破坏准则 上限定理 曲线形破坏机制 浅埋洞室 

分 类 号：TU921[建筑科学—建筑设计及理论]