地下厂房施工过程的三维非线性数值模拟分析

根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。

Three-Dimensional Nonlinear Numerical Analysis on the Construction Process of Underground Powerhouse

With the underground powerhouse in Rongge power station as a case study, three-dimensional non-linear finite element method was employed to simulate the dynamic process of excavation and supporting of cavern groups. The anchor was simulated by implicit bar element and the concrete spray layer was simulated by shell element. The regularity of stress deformation distribution of the surrounding rock during dynamic excavation, development of plastic zone in the surrounding rock, and the variation of anchor stress were obtained. Results showed that the variation of surrounding rock displacement was normal and the value was very small. The plastic zone  mainly distributed around the underground caverns and the surrounding rock was stable during the whole excavation. However, the surrounding rock displacement was larger in the intersection of caverns, and wide plastic zone appeared there. Optimized supporting measure was put forward, and the effect was assessed.