基于岩腔后退的危岩断裂破坏分析——以重庆市万州区太白岩危岩为例  

Fracture Failure Analysis of Unstable Rocks Due to Rock-Cell Retreating——A Case Study of Unstable Rocks in Taibaiyan, Wanzhou District, Chongqing Municipality, China

作　　者：周云涛[1,2] 蔡强 谢忠胜[1,2] 梁炯 ZHOU Yuntao;CAI Qiang;XIE Zhongsheng;Liang Jiong(Institute of Ezploration Technology CAGS,Chengdu 611734,China;Technology Innovation Center for Risk Prevention and Mitigation of Geohazard,Ministry of Natural Resources,Chengdu 611734,China)

机构地区：[1]中国地质科学院探矿工艺研究所,四川成都611734 [2]自然资源部地质灾害风险防控工程技术创新中心,四川成都611734

出　　处：《防灾减灾工程学报》2023年第1期138-148,共11页Journal of Disaster Prevention and Mitigation Engineering

基　　金：国家重点研发计划专项课题(2019YFC1509904);中国地质调查项目(DD20221745)资助。

摘　　要：硬质岩体危岩的突发性破坏本质是岩体的脆性断裂破坏。以重庆市万州区太白岩危岩为例,将危岩后缘卸荷裂隙的扩展贯通简化为半无限大板的边缘裂纹断裂问题,建立了卸荷结构面接触与非接触的裂纹断裂力学模型,推导了Ⅰ型裂纹、Ⅱ型裂纹应力强度因子以及联合应力强度因子表达式,并基于数值模拟手段提出了危岩结构面正应力与剪应力确定方法。万州太白岩危岩W10断裂破坏分析结果表明:危岩崩塌失稳受控于岩腔的深度,岩腔深度加大,后缘卸荷裂隙扩展,其力学机制根据岩腔深度变化表现为拉破坏和拉剪破坏;对于危岩W10,裂纹联合应力强度因子随岩腔深度的增大表现出先增加后降低再增大的趋势,Ⅰ型裂纹断裂应力强度因子具有与联合应力强度因子相同的变化特征;岩腔深度3~6 m以及9~10 m内,危岩裂纹主要为拉应力集中状态;岩腔深度6~9 m时,危岩裂纹处于拉剪应力状态;当岩腔深度为3.8 m时,危岩W10发生拉剪断裂破坏,断裂扩展角为29.5°。The nature of sudden failure of unstable hard rock is brittle fracture. Taking unstable rocks in Taibaiyan, Wanzhou District, Chongqing Municipality, China, as an example, this paper simplified the extension and connection of unloading cracks at the back edge of unstable rock as the edge crack fracture of semi-infinite plate. Then it established the mechanical models of crack fracture, and deduced expressions of stress intensity factors and unite stress intensity factors for model-Ⅰ crack and model-Ⅱ crack. Calculation methods of normal stress and shear stress at structural surface of unstable rocks were proposed using numerical simulations. This fracture failure of unstable rock W10 was analyzed, and it can be concluded that unstable rock collapse was controlled by rock-cell depth. When the depth of the rock-cell increased, the unloading fissure at the back edge expanded, and its mechanical mechanisms were tensile failure and tensile shear failure according to the variation of the depth of the rock-cell. For unstable rock W10, the unite stress intensity factor first increased, then decreased and finally increased with rock-cell depth increasing, and the stress intensity factor for model-Ⅰ crack had the same characteristics as the unite stress intensity factor. When the rock-cell depth was 3-6 m and 9-10 m, crack fracture failure was controlled by concentration tension stress. When the rock-cell depth was 6 meters to 9 meters, crack fracture failure was controlled by concentration tension-shear stress;when the rock-cell depth was 3.8 m, unstable rock W10 collapsed and its extension angle was 29.5°.

关 键 词：断裂力学模型 应力强度因子 断裂判据 危岩 岩腔 

分 类 号：P642.21[天文地球—工程地质学] O346.11[天文地球—地质矿产勘探] X935[天文地球—地质学]