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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 mechanics and deformation characteristics of underground structures located in saturated soils are quite different from those in completely dried soils. According to the nonlinear failure characteristics of shallow underground caverns, a new curvilinear failure mechanism is constructed, and the pore water pressure power is introduced as an external force into the virtual power equation of the upper bound limit analysis theorem, and the pore water pressure effect Analytical expressions of the upper bound of discontinuous line between support force and velocity in shallow cavern in saturated soils. By using the variational principle, the upper bound solution of the supporting force is optimized and the optimal upper bound solution of the supporting force is obtained. The variation of the supporting force under the single influence parameter varies with the depth of the roof and the top of the cave The shape of the rake was studied. The results show that the pore water pressure has a great influence on the supporting force and the collapse surface of the shallow cavern in saturated soil. Both the supporting force and the collapse surface increase with the increase of the pore water pressure coefficient.