江边水电站地下洞室群围岩稳定性数值分析

利用显式有限差分快速拉格朗日分析程序FLAC3D,在进行初始地应力反演的基础上,建立了四川江边水电站地下厂房洞室群的三维非线性地质力学模型。采用基于能量耗散原理的弾脆性本构模型,对设计开挖和支护方案进行了全过程模拟分析,得到了施工过程中洞室群围岩的位移、应力和塑性区分布特点,并与现场监测情况进行比对,根据分析结果提出了加强监测的位置、加强支护的部位,并建议主厂房下游边墙和主变洞上游边墙之间区域采用预应力锚索进行重点加强,最后对支护系统和建议的合理性进行评价,对地下洞室群的设计和施工起到了一定的指导作用。

Numerical Analysis of the Surrounding Rock Stability of the Underground Cavern Group at Jiangbian Hydropower Station

Based on the back analysis of rock mass initial stress field, the 3D nonlinear finite element model of Jiangbian Hydropower Station was established by using explicit finite difference fast Lagrangian analysis of continua program FLAC3D. Considering the theory of energy dissipation, an elasto-brittle constitutive model was used in this paper to simulate the whole process of excavation and support, and then obtain the displacement, stress and plastic zone distribution, at the same time compare the simulated result with the on-site monitoring data. According to results of analysis, the positions to strengthen the monitoring and support sites were proposed, and it was suggested that the region between downstream side wall of main plant and the upstream side wall of main transformer cave should be strengthened using prestressed anchor. At last, the reasonableness of support systems and relevant recommendations as evaluated, which could be used to guide the design of excavations and rock supporting work.