围岩参数不确定性对地下水封洞库稳定性的影响

Influence of parameter uncertainty on stability of underground water-sealed cavern

为了分析库区围岩条件测量不确定性问题对围岩稳定性分析产生的影响,依托国内某地下水封洞库工程,采用ANSYS/FLAC3D建立洞库的三维数值计算模型,开展洞库稳定性数值模拟。将围岩的位移分布、应力分布和塑性区分布作为稳定性的评价指标,分析围岩物理力学参数(包括弹性模量、泊松比、密度、内摩擦角、黏聚力和抗拉强度)、地应力方向对洞库围岩稳定性的影响。通过改变围岩物理力学参数的大小和应力场方向,开展考虑围岩物理力学参数和主应力方向不确定性的地下水封洞库围岩稳定性研究。数值模拟结果表明,当围岩的物理力学参数下降10%时,围岩的位移显著增加,地应力方向改变10%时,围岩位移变化均会增加,说明围岩物理力学参数的变化对稳定性的影响更大,验证主洞室的走向应与地应力方向平行。

In order to analyze the impact of uncertainty in measuring the surrounding rock conditions in the reservoir area on the stability analysis of the surrounding rock,a three-dimensional numerical calculation model of caving was established using ANSYS/FLAC3D based on a domestic underground water-sealed cavern project,and numerical simulation of the cave stability was carried out.The displacement distribution,stress distribution and plastic zone distribution of surrounding rock were taken as the evaluation indicators of stability,and the influence of physical and mechanical parameters of surrounding rock(including elastic modulus,Poisson's ratio,density,internal friction angle,cohesion and tensile strength)and in-situ stress direction on the stability of surrounding rock of cavern was analyzed.By changing the size of the physical and mechanical parameters of the surrounding rock and the direction of the stress field,the study on the stability of the surrounding rock of underground water sealed caverns was carried out considering the uncertainty of the physical and mechanical parameters of the surrounding rock and the direction of the main stress.The numerical simulation results showed that when the physical and mechanical parameters of the surrounding rock decreased by 10%,the displacement of the surrounding rock increased significantly.When the direction of the in-situ stress changed by 10%,the displacement of the surrounding rock would increase.It showed that the change of physical and mechanical parameters of surrounding rock had a greater impact on the stability,and it verified that the strike of the main cavern should be parallel to the direction of crustal stress.