金川水电站左岸引水发电系统进水口高边坡稳定性分析

Stability analysis of the high side slope near the inlet of the diversion power system on the left bank of the Jinchuan Hydropower Station

金川水电站左岸引水发电系统进水口边坡开挖高度约160m,边坡稳定性是该工程的主要地质问题之一。通过现场详细勘察,在分析该边坡的地层岩性、坡体结构、结构面及其组合、风化卸荷等工程地质特征基础上,建立了边坡和结构面的三维地质模型,结合边坡的开挖设计,进行平行和垂直轴向边坡方向的剖切,从而得到块体组合情况。然后,利用岩石边坡块体稳定性计算程序对各潜在不稳定块体进行计算。在现场统计坡比基础上,就如何选定一个安全经济的坡比进行探讨。采用有限元法对不同工况下的边坡稳定性进行了分析与评价,为设计和施工提供了科学依据。

The inlet excavation of the diversion power system of the Jinchuan Hydropower Station results in a slope of about 160 m height,whose stability is one of the main geological problems of the project.Through detailed investigation of the site,this paper analyzes the engineering geological characteristics of the intake slope,including lithology,slope structure,structural surface and its combinations,rock weathering and unloading,hydrology,etc.A 3-D geologic model of slope and structural surface is established with space coordinate.Under the consideration of the slope excavation design,slices of the parallel and vertical axial side slope are carried out.Thus,the block body combination situations are obtained.The stability of potentially unstable blocks is calculated by means of business analysis software for the stability of rock slope wedges.On the basis of site slope ratio statistics,the problem of how to select a safe and economic excavation slope ratio is studied.The finite element method is used to calculate and analyze the deformation and stress states and the safety factors for three kinds of working conditions(including natural condition,rainstorm condition and earthquake condition).The results of analysis and evaluation provide a scientific basis for the design and construction of the project.