基于极限平衡法高边坡稳定性分析方法

High slope stability analysis method based on limit equilibrium method

岩石高边坡是山区水电站工程建设中的主要地质环境,尤其在我国西部地区,高边坡问题作为重大工程的关键技术问题之一,控制着工程建设的可行性和经济效益,因此有必要对其进行分析研究。以如美水电站中坝址高陡边坡稳定性分析为目标,基于二维极限平衡法,结合现场勘查、理论分析和Geo-Studio数值模拟,考虑如美水电站中坝址高陡边坡的三种不同节理组合形式,在降雨工况和地震工况下对边坡整体稳定性进行分析评估。研究结果表明,降雨工况对边坡稳定性影响远大于地震工况,产生塑性区的范围相较于地震工况更大,在开挖卸荷工况下,边坡受到较大扰动产生卸荷区,发生失稳破坏。基于数值模拟结果,得到满足工程实际的结构面选取方式。

The rock high slope is the main geological environment of the hydropower project construction in the mountainous area,especially in the western area of our country,the high slope problem has become one of the key technical problems of the important project,controlling the feasibility and economic benefit of the project construction,so it is necessary to analyze and study it.This paper aims at the stability analysis of the high and steep slope at the middle dam site of Rumei Hydropower Station,based on the two-dimensional limit equilibrium method,combined with the on-site investigation,theoretical analysis,and Geo-Studio numerical simulation,and considering three different joint combinations of the high and steep slope at the middle dam site of Rumei hydropower station,the overall stability of slope was evaluated under rainfall and earthquake conditions.The results show that the influence of rainfall conditions on slope stability is much greater than that of earthquake conditions,and the plastic zone is larger than that of earthquake conditions.Under the excavation unloading condition,the slope is disturbed greatly to produce an unloading area,and instability failure occurs.Based on the numerical simulation results,the structure surface selection method satisfying the engineering practice is obtained.