复杂地质结构下地下厂房布置方案的对比分析

岩滩水电站扩建工程地下厂房为大跨度、高边墙大型洞室,且上、下发育有石英岩脉与f 211构造挤压破碎带.针对这种上、下被不利地质结构所包围的地下厂房, 采用二维弹塑性有限元方法对多种布置方案下的施工开挖进行了数值模拟,分析了围岩的开挖变形与应力随开挖的演变过程.在保证地下厂房围岩整体稳定性的条件下,对地下厂房布置方案进行了比较优化,论证了合理的布置方案.分析结果表明:(1)石英岩脉力学性状及其相对于地下厂房的位置对围岩稳定性影响不明显;(2)f 211是影响厂房区岩体稳定的主要不利地质结构;(3)建议针对f 211出露部位施加相应的支护措施,这样对限制不利地质结构对围岩稳定性的影响将有明显效果.

Comparison Analysis of the Location Scheme of Power House Surrounded by Complex Geological Structure

The power house of Yantan extended hydropower project is a huge underground cavern with large span and high wall.There exist complex geological conditions such as fault f211 below the power house and quartzite on top of it.For evaluating the stability of the powerhouse surrounded by such complex geological structure,the numerical simulation excavation of power house with different location schemes was studied by using the elasto-plastic 2D FEM method.The surrounding rock mass excavation deformation and evolutive process of the stress with the progress of excavation were analyzed.On the condition to ensure the whole stability of surrounding rock mass,comparison optimization analyses were conducted on the power house location scheme and the rational location scheme was demonstrated.Analyses results show that:(1) The mechanical properties of quartzite and its relative location to the power house has no obvious influence to the stability of surrounding rock mass.(2) the f 211 is the main unfavorable geological structure which affects the stability of power house.(3) Supporting measures,at the out-crop of f 211 are suggested which would have an obvious effect to control the influence of unfavorable geological structure on the stability of surrounding rock mass.