平行地裂缝地铁隧道土压力计算方法

Earth Pressure Calculation Method of Metro Tunnel Parallel to Ground Fissures

针对西安地铁三号线工程部分区间段存在近距离平行西安地裂缝的工程现象,通过力学解析方法对地铁隧道所受土压力进行分析。在建立平行地裂缝地铁隧道力学模型的基础上,根据所取计算单元的极限平衡条件推导得到隧道竖向土压力和水平土压力,并通过拟静力化的方法对地震作用进行简化,分析地震动荷载作用下隧道土压力特征。计算结果表明,地裂缝活动导致上盘产生竖向土压力减小区,而下盘出现竖向土压力增大区。根据规范推荐的方法对平行地裂缝的地铁隧道进行设计是合理的。

In view of the engineering phenomenon of short distance parallel to Xi＇an ground fissure in some interval sections of No. 3 line of Xi＇an metro project,through the analytical method of mechanics,the soil pressure to metro tunnel is analysed. Based on building the mechanical model of the metro tunnel parallel to ground fissure,the vertical earth pressure and horizontal earth pressure of tunnel are derived according to the limit equilibrium condition of the calculated units,and through the pseudo static method,the seismic action is simplified,the characteristics of tunnel soil pressure under the ground motion load are analysed. The calculation results show that the activity of ground fissure leads to vertical earth pressure decreasing area on the upper wall,while the vertical soil pressure increases in footwall. It is reasonable to design the metro tunnel parallel to ground fissure according to the method recommended by the code.