露天矿含后缘裂隙岩质边坡岩体卸荷断裂机理与稳定性研究  

Mechanism and stability of unloading fracture in rock slopes containing trailing edge cracks in open pit mines

作　　者：王建明 崔新男 陈忠辉[2] 陈冲 WANG Jianming;CUI Xinnan;CHEN Zhonghui;CHEN Chong(Ansteel Beijing Research Inititute CO.,LTD.,Beijing 100029,China;School of Mechanics&Civil Engineering,China University of Mining and Technology,Beijing 100083,China)

机构地区：[1]鞍钢集团北京研究院有限公司,北京102209 [2]中国矿业大学(北京)力学与建筑工程学院,北京100083

出　　处：《岩土工程学报》2023年第2期345-353,共9页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(52074292);国家重点研发计划课题(2017YFC1503103)。

摘　　要：基于边坡实际结构特征,利用断裂力学理论,推导了卸荷作用下后缘裂隙尖端的应力强度因子和临界失稳高度计算公式,考虑分支裂隙扩展长度,构建了边坡岩体裂隙扩展贯通力学模型,提出了边坡稳定性系数计算方法,并通过工程实例来验证。结果表明:(1)卸荷作用越强,后缘裂隙尖端复合应力强度因子越大,边坡的稳定性越差。(2)后缘裂隙倾角越大,临界扩展高度越小,起裂角越大,裂隙越来越趋向于边坡坡面扩展;平均高度越大,临界扩展高度越小,起裂角越大,裂隙越来越偏离边坡坡面扩展;裂隙长度对临界扩展高度和起裂角没有影响。(3)边坡安全系数随后缘裂隙倾角、平均高度和断裂韧度的增加而增大,随裂隙长度、下部裂隙角度和卸荷拉应力的增加而减小。研究成果可为认识和治理卸荷诱发含后缘裂隙岩质边坡崩塌滑坡灾害提供一定理论参考。Based on the real structural characteristics of slopes and using the theory of fracture mechanics,the formulas for calculating the stress intensity factor and the critical instability height of trailing edge crack tip under unloading are deduced,Considering the extension length of branch cracks,the mechanical model for crack expansion in slope rock mass is established,and the method for the stability coefficient of slopes is put forward,and is verified through an engineering example.The results show that:(1)The stronger the unloading effects,the greater the intensity factor of compound stress at the tip of the trailing edge crack,and the worse the stability of the slope.(2)The larger the inclination angle of the trailing edge crack,the smaller the critical expansion height and the larger the crack initiation angle.The larger the average height,the smaller the critical expansion height,and the larger the crack initiation angle.The crack is more and more deviating from the slope expansion,and the crack length has no effects on the critical propagation height and the initiation angle.(3)The factor of safety of the slope increases with the increase of the crack inclination angle,average height and fracture toughness,and decreases with the increase of the crack length,lower crack angle and unloading tensile stress.The research results may provide some theoretical reference for understanding and controlling the collapse and landslide disasters of rock slopes with trailing edge cracks induced by excavation unloading.

关 键 词：开挖卸荷 后缘裂隙 起裂角 分支裂隙 安全系数 

分 类 号：TU452[建筑科学—岩土工程]