基于断裂力学的高寒地区边坡危岩体稳定性分析

Stability analysis of slope dangerous rock mass in alpine region based on fracture mechanics

高寒地区露天矿山中的危岩体受冻融作用影响时常发生滑塌,为保障露天矿山企业持续生产,对矿山靠帮边坡中存在的危岩体进行基于断裂力学的稳定性分析。以高寒地区某露天矿山为工程背景,分析冻融循环对工程影响,首先建立不同时间点温度场,结合温度场提出一种方法来判定冻融深度是否能影响主控结构面产生冻胀力。引入最大周向应力准则对坡体中出现的拉裂缝进行分析,进而推导出安全系数表示方法。以反倾岩质边坡为研究主体,将边坡危岩体拆分为n个潜在不稳定的近似矩形岩体,并基于此建立考虑冻胀力、裂隙水压力与重力共同作用的断裂力学边坡稳定性计算方法。针对相应算例,通过该方法计算得到分割后各岩体的安全系数,并发现冻胀力对岩体稳定性有一定程度影响,结合工程实际验证了提出方法的可行性。最后结合相关危岩稳定性评价标准,针对不同岩体稳定性情况提供相应治理措施。

In order to ensure the continuous production of open-pit mining enterprises,the stability analysis of dangerous rock mass in mine slope based on fracture mechanics is carried out.Taking an open-pit mine in an alpine area as the engineering background,in order to analyze the impact of the freeze-thaw cycle on the project,firstly,the temperature fields at different time points are established,and combined with the temperature field,a method is proposed to determine whether the freeze-thaw depth can affect the main control structural plane to produce frost heaving force.The maximum circumferential stress criterion is introduced to analyze the tensile cracks in the slope,and then the expression method of safety factor is derived.Taking the anti-inclined rock slope as the research subject,the dangerous rock mass of the slope is divided into n potentially unstable approximate rectangular rock masses.Based on this,a fracture mechanics slope stability calculation method considering the combined action of frost heaving force,fracture water pressure and gravity is established.According to the corresponding calculation example,the safety factor of each rock mass after segmentation is calculated by this method,and it is found that the frost heaving force has a certain impact on the stability of rock mass.Combined with the engineering practice,the feasibility of the proposed method is verified.Finally,combined with the relevant evaluation standards of dangerous rock stability,suitable treatment measures are provided for different rock mass stability.