危岩水力劈裂分析的扩展有限元法  

An extended finite element method for modeling hydraulic fracturing in perilous rock

作　　者：郑安兴 罗先启[2] ZHENG An-xing;LUO Xian-qi(School of Water Conservancy and Environmental Engineering,Zhejiang University of Water Resources and Electric Power,Hangzhou,Zhejiang 310018,China;School of Naval Architecture,Ocean and Civil Engineering,Shanghai Jiaotong University,Shanghai 200240,China)

机构地区：[1]浙江水利水电学院水利与环境工程学院,浙江杭州310018 [2]上海交通大学船舶海洋与建筑工程学院,上海200240

出　　处：《岩土力学》2018年第9期3461-3468,3476,共9页Rock and Soil Mechanics

基　　金：浙江省自然科学基金资助项目(No.LQ18E090003);国家自然科学基金资助项目(No.51279100)~~

摘　　要：危岩是三峡库区典型的地质灾害类型之一,而主控结构面受荷断裂扩展是危岩发育成灾的关键核心。将危岩主控结构面类比为宏观裂纹,利用扩展有限元法在模拟裂纹扩展方面的优势,基于考虑裂纹面水压力作用的虚功原理推导出了采用扩展有限元法分析水力劈裂问题的控制方程,给出了危岩主控结构面水力劈裂问题的扩展有限元实现方法,对重庆万州太白岩危岩主控结构面的水力劈裂进行了数值模拟分析。计算结果表明:暴雨是威胁危岩稳定性的最敏感因素,随着裂隙水压力上升,裂端拉应力会急剧升高,危岩的稳定性降低;I型裂纹扩展是危岩主要的结构面扩展形式,结构面一旦发生开裂,将处于非稳定扩展状态。The perilous rock is one of the typical disasters in the Three Gorges reservoir region. Crack propagation of controlling joint under loads is the key process in failure of perilous rock. The extended finite element method（XFEM） is an effective approach for fracture analysis. The governing equation of XFEM for hydraulic fracture modeling is derived by the virtual work principle of the fracture problem considering the water pressure on crack surface. Then the implement method of XFEM for hydraulic fracture modeling is deduced. The Taibaiyan cliff at Wanzhou is a representative case of massive perilous rocks in the area. The hydraulic fracturing process on this site is simulated and analyzed by extended finite element method. The numerical analysis results show that water pressure in controlling joint of perilous rock is sensitive to the rainstorm condition. With the increases of water pressure in control joint, the tensile stress at the crack tip increases rapidly and the stability of perilous rock decreases; type I crack propagation is the main form of crack propagation in perilous rock and the crack propagation is non-steady propagation.

关 键 词：危岩 水力劈裂 扩展有限元法 断裂 数值模拟 

分 类 号：TU452[建筑科学—岩土工程]