随着地下洞室的大量兴建,且埋深越来越深,深埋地下洞室的开挖稳定性问题显得非常重要。针对深埋隧洞围岩特殊的力学特性表现,采用应变软化模型进行数值分析更为合适。首先,对深埋隧洞围岩力学特性和岩石应变软化模型进行简单分析,并且通过数值加载试验分析了Mohr-Coulomb弹塑性模型和应变软化模型计算得到岩石应力-应变关系之间的区别。然后,对简单圆形深埋隧洞进行数值分析,对比分析了Mohr-Coulomb弹塑性模型和应变软化模型计算结果之间的差别,分析主要针对围岩的变形、塑性区和安全系数。最后,采用应变软化模型对两家人水电站深埋地下洞室群进行计算分析,对该地下洞室群的开挖稳定性进行评价。计算结果表明,调压室主室两侧边墙和各洞室连接处的变形较大,较其他地方更危险,需要加强对调压室主室边墙和各洞室连接处的支护强度。
Along with the construction of underground caverns in depths, the stability of deep underground cavern excavation is a hot issue. According to the special mechanical behaviors of rock in deep tunnel, the strain-softening model is more suitable for numerical analysis. First, the mechanical properties of surrounding rock in deep tunnel and rock strain-softening model are simply analyzed; and through a simple numerical loading example of rock, the stress-strain computation results of Mohr-Coulomb elastoplastic model and strain-softening model are analyzed. Then, a simple circle deep tunnel numerical analysis is carried out; and the comparative analysis of computation results of Mohr-Coulomb elastoplastie model and strain-softening are analyzed~ mainly for the analysis of the surrounding deformation, plastic zone and factor of safety. Finally, the strain-softening model is used to the deep underground caverns of Liangjiaren Hydropower Station~ and the stability of underground caverns is evaluated.The results show that the deformations of both sides of main cavern and the junction cavern are larger, more dangerous than other places. The support of the both sides of main cavern and junction cavern should be considered.