岩石力学参数对地下洞室群围岩变形的敏感性分析

岩石力学参数的不确定性是影响地下洞室群围岩稳定性分析的主要因素。以某水电站地下厂房为例,结合工程区域的地质条件,建立三维弹塑性有限元模型,通过单因素敏感性分析方法分析了岩石块体和断层的弹性模量、粘聚力、内摩擦角和泊松比对洞室开挖完成后典型机组断面关键点位移的敏感性。结果表明,顶拱处岩石块体内摩擦角为最敏感参数,其次为块体弹性模量;边墙区域岩石块体弹性模量、内摩擦角敏感性最大;而断层参数的敏感性均较小。因此对该工程进行参数选取时,需对岩石块体弹性模量和内摩擦角加以评估并进行精细化测定,提高数值模拟结果的可靠性。研究成果可为类似工程提供借鉴。

Sensitivity Analysis of Rock Mechanical Parameters to Deformation of Surrounding Rock of Underground Caverns

The uncertainty of rock mechanics parameters is the main factor affecting the stability analysis of surrounding rock of underground caverns. Taking an underground powerhouse of a hydropower station as an example, considering the geological conditions of the engineering area, a three-dimensional elastoplastic finite element model was established. And then the sensitivity of the elastic modulus, cohesion, internal friction angle and Poisson ratio of rock block and fault to the displacement of key points of the typical unit sections after excavation was analyzed based on the single factor sensitivity analysis method. The results show that at the top of the arch, the internal friction angle of rock block is the most sensitive parameter, followed by the elastic modulus of the block; The elastic modulus and the internal friction angle of rock block are the most sensitive to the side wall region; The sensitivity of fault parameters is small. Therefore, when choosing the parameters of the project, the elastic modulus and internal friction angle of rock block need to be evaluated and measured accurately so as to improve the reliability of numerical simulation. The research results can provide reference for similar projects.