龙滩水电站地下洞室群围岩变形与稳定性的二维弹塑性分析

2-D Elas-plastic Analysis on Deformation and Stability of Rock Mass in Powerhouse Area of Longtan Hydropower Station

龙滩水电站是红水河上的关键工程,其主要特点是地下建筑洞群结构复杂,规模巨大,且岩层为陡倾角层状结构岩体;两者的耦合作用,使洞室群围岩的稳定性,特别是主厂房与调压井的高边墙、洞室交叉口部位的变形稳定性尤显复杂,倍受关注.本文通过对龙滩工程厂房区地质调查,结合洞群结构分析,建立了工程地质概化模型,采用二维弹塑性有限元对地下厂房洞室群的施工开挖进行模拟,对比分析了多种不同条件下的洞室群开挖变形、应力以及屈服区的分布特征,获得了一些有益于指导施工的结果.

The Longtan hydroelectric station is a key project over the Hongshui River. One important feature of the project is the numerous and jumbled underground opening, and the rock mass is steep-obliquity geologic-structure body. Therefore, the stability of the rock mass around the powerhouse because of excavation under the coupling of rock mass and powerhouse cavern, especially near the high border-wall and across part of cavern, is more complicated and catches much of attention of many people. In this paper, we set up a geologic simplified-model after investigating engineering geological characterization of powerhouse area of the project and analyzing the construction of the underground powerhouse, apply the 2-D FEM to simulate the coures of excavation of the powerhouse. We design many schemes to contrast and analyze the deformation,stress and plastic area under different conditions and obtain the distribution of their characterization. In the end we result some valuable conclusion which is benefit for excavation.