摘要
乌东德水电站右岸地下厂房洞室群密集、开挖规模大、地质条件复杂,开挖期间变形破坏问题突出。在地应力实测资料、工程地质特性、开挖过程分析的基础上,利用离散元程序对右岸地下厂房开挖过程进行数值模拟,再现不同模型的应力场、位移场演化过程,分析陡倾角层面对于主厂房变形的影响作用。同时,构建高精度微震监测系统,对开挖诱发的微震活动实时在线监测;分析微震事件聚集规律、S波及P波能量比值Es/Ep分布特征,识别和圈定潜在风险区域,揭示围岩变形机制。微震监测与数值模拟结果表明:在开挖卸荷作用下,陡倾角层面附近岩石破裂,微震事件聚集,能量释放,引起围岩变形破坏。围岩以结构面控制的应力驱动型张拉破坏为主,并伴随少量重力驱动型变形。该研究结果为乌东德水电站地下厂房的开挖和支护设计方案提供重要依据。
The right bank underground caverns of Wudongde hydropower station are dense and large-scale, and the geological stratification is complex, which results in severe deformation and failure problems during excavation. Based on the analysis of the characteristics of geologic framework, in-situ stress data and excavation consequence of underground caverns, a numerical model was established to investigate the stability of the right bank underground powerhouse during excavation unloading by using the discrete element method（DEM）. In the numerical modelling, we studied the principal stress fields and deformation fields, and analysed the deformation mechanism of the structural planes with a steep dip angle. Then, a high-precision microseismic（MS） monitoring system was established to evaluate the stability of the surrounding rock during excavation. Their assembling rules of MS events and energy ratio Es/Ep were analysed to identify the potential failure regions and deformation mechanism. The combined numerical simulation and MS monitoring indicated that under the excavating unloading, the failure of rock masses was observed near the layered rock with the steep dip angle where MS events assembled and the energy released, which results in surrounding rock failure. The deformation of surrounding rock was largely induced by stress-driven tensile failure which was controlled by structural planes. The results provide important references for excavation and reinforcement of the right bank underground caverns at Wudongde hydropower station.
作者
胡中华
徐奴文
戴峰
顾功开
李昂
杨莹
HU Zhong-hua;XU Nu-wen;DAI Feng;GU Gong-kai;LI Ang;YANG Ying(State Key Laboratory of l-tydraulics and Mountain River Engineering,Sichuan University,Chengdu,Sichuan 610065,China;China Three Gorges Corporation,Beijing 100038,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2018年第10期3794-3802,3811,共10页
Rock and Soil Mechanics
基金
国家自然科学基金面上项目(No.51679158)
国家重点基础研究发展计划(973计划)(No.2015CB057903)~~
关键词
地下厂房
离散元
层状岩体
微震监测
变形
underground powerhouse
distinct element
layered rock mass
microseismic monitoring
deformation
