极限平衡方法在夏日哈木镍钴矿山拟建露天采场边坡角优化中的应用

Application of Limit Equilibrium Method in Slope Angle Optimization of the Proposed Open pit in Xiarihamu Nickel and Cobalt Deposit

夏日哈木镍钴矿为大型镍钴硫化物矿床,现拟建大型露天采场,边坡采用分台阶式高边坡,最高边坡高度超过600 m。该工程具有开挖成本高,边坡一但失稳后果严重的特点。为此需要选择一个即节约经济成本又保障整体边坡稳定的最佳边坡角。本文采取Geostudio软件中的Slope模块极限平衡方法对拟建露天采场假设开挖边坡角的整体边坡稳定性进行分析,提出最佳设计边坡角。本次边坡角优化的思路:首先根据场地工程地质条件和拟建边坡的高度等因素将拟建边坡划分为5个区,选择典型边坡工程地质剖面并进行工程地质岩体分段,然后通过岩石强度指标折减计算(本文采用费辛柯法、M.Georgi法和经验法)给各分段的岩体赋予凝聚力、内摩擦角等计算参数,采用极限平衡方法(Geostudio软件中的Slope模块法)对不同角度下对各分区边坡的破坏形式及安全系数进行计算,最后提出了各分区边坡的最佳设计边坡角。

Xiarihamu nickel and cobalt deposit is a large scale nickel and cobalt sulfide deposit.Now,a large open-pit stope is to be built.The side slope is of stepped type with the maximum height of more than 600 m.The project is an important project,which has the characteristics of high excavation cost and serious consequences of slope instability.Thus,it is necessary to choose an optimal slope angle which can save economic cost and ensure the stability of the whole slope.In this paper,the slope module limit equilibrium method in GeoStudio software is used to analyze the overall slope stability of the proposed open pit excavation slope angle,and the optimal design slope angle is proposed.The idea of slope angle optimization is as follows:firstly,according to the site engineering geological conditions and the height of the proposed slope and other factors,the proposed slope is divided into five areas,typical slope engineering geological section is selected and the engineering geological rock mass is segmented,then the rock mass of each section is endowed with cohesion and internal strength through the reduction calculation of rock strength index(this paper adopts fischenko method,M.Georgi method and empirical method).According to the calculation parameters,such as friction angle,the limit equilibrium method(slope module method in GeoStudio software)is used to calculate the failure mode and safety factor of slope in different sections under different angles.Finally,the optimal design slope angle of each partition slope is proposed.