陡倾角层状岩层大型地下厂房施工期围岩变形开裂机理研究  

Deformation and Cracking Mechanism of Surrounding Rock Mass of Large Underground Powerhouse in Steeply Dipped Rock Strata

作　　者：周述达 丁秀丽[2] 裴启涛[2] 卢波[2] 黄书岭[2] 吴勇进[2] 

机构地区：[1]长江勘测规划设计研究院,湖北武汉430010 [2]长江科学院水利部岩土力学与工程重点实验室,湖北武汉430010

出　　处：《四川大学学报（工程科学版）》2016年第6期90-98,共9页Journal of Sichuan University (Engineering Science Edition)

基　　金：国家自然科学基金资助项目(51539002;51609018;51379022);国家重点研发计划资助项目(2016YFC0401802)

摘　　要：针对乌东德水电站右岸地下主厂房在引水洞下平段L3支洞顶拱开挖过程中,7#、8#机组段上游边墙出现的围岩变形快速增长和沿层面开裂等变形破坏现象,结合地质、监测、物探及施工资料,分析主厂房围岩变形与破坏特征。基于此,从岩体结构、地应力状态、施工过程等角度出发,结合3维离散元数值仿真手段,对围岩变形开裂机制进行综合论证和深入探讨。结果表明:小夹角顺倾下游的陡倾层状岩体结构是造成7#、8#组段上游边墙变形快速增长并呈现一定时效特征的地质基础;L3支洞顶拱施工速度过快,从而产生了强烈的围岩卸荷扰动效应,导致上游边墙围岩一定深度范围内岩体沿层面张开和滑移,引起围岩变形的突然性快速增长;陡倾角层状岩体的围岩变形开裂特征对L3支洞顶拱开挖规模及扰动较为敏感,合理控制岩体开挖规模及卸荷扰动效应能够有效地减小围岩变形、结构面错动和张开现象。研究成果可为类似陡倾角大跨度地下工程开挖的稳定性分析及支护设计提供借鉴。As the excavation of auxiliary opening L3 at the right bank of underground cavern in Wudongde hydropower station was carried out, the excavation disturbance led to rapid growth of surrounding rock deformation and surface rupture along interlayers of rock mass. The characteristics of deformation and failure of surrounding rock was preliminarily described based on the geological conditions, monitoring and geophysical prospecting data, and construction process. On the basis, deformation and cracking mechanism of surrounding rock mass was discussed by combining the surrounding rock mass structure characteristics, geostress and construction process as well as the three dimensional distinct element method. The resuhs were as follows. The steeply dipped rock strata was basic condition which caused rapid and continuous growth of surrounding rock deformation at upstream side wall of 7# ,8# unit since the excavation of auxiliary opening L3. The upstream side wall was exposed to considerable excavation disturbance effect due to the rapid construction of auxiliary opening L3. Then, the upstream side wall surrounding rock became a weak link and caused surface either open or slip. The characteristics of deformation and failure of steeply dipped rock strata was very sensitive to excavation disturbance, which could be effectively reduced through reasonable control of the scale excavation and unloading disturbances. The results could provide an important reference for stabihty analysis and design support of similar steeply dipped rock strata of large span underground projects.

关 键 词：地下工程 乌东德水电站 陡倾角岩层 变形开裂机理 3维离散元 

分 类 号：TU452[建筑科学—岩土工程]