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

发布时间：2018-01-12 22:23

本文关键词：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　出处：《四川大学学报(工程科学版)》2016年06期 　论文类型：期刊论文

【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。
[Abstract]:The main underground powerhouse on the right bank of Wudongde Hydropower Station is excavated during the excavation of the L3 branch arch in the horizontal section of the diversion tunnel. The deformation and failure phenomena of surrounding rock such as the rapid growth of surrounding rock deformation and cracking along the plane of the upstream side wall in the upper reaches of the power unit are analyzed. Combined with geological monitoring geophysical prospecting and construction data the deformation and failure characteristics of the surrounding rock of the main powerhouse are analyzed. From the point of view of rock mass structure, in-situ stress state, construction process and so on, combined with 3D discrete element numerical simulation method. The mechanism of deformation and cracking of surrounding rock is comprehensively demonstrated and deeply discussed. The results show that the structure of steeply inclined layered rock mass downstream with small angle is the cause of "7#". The geological foundation of the deformation of the upstream side wall of the 8# formation is increasing rapidly and showing certain time-dependent characteristics; The construction speed of L3 roof arch is too fast, which results in the strong disturbance effect of surrounding rock unloading, which leads to the rock mass opening and sliding along the plane in a certain depth range of upstream side wall rock. The sudden increase of surrounding rock deformation; The deformation and cracking characteristics of rock mass with steep dip angle are sensitive to the excavation scale and disturbance of the roof arch of L3 branch tunnel. Reasonably controlling the excavation scale of rock mass and the effect of unloading disturbance can effectively reduce the deformation of surrounding rock. The research results can be used for reference for the stability analysis and support design of similar steep inclined large span underground engineering excavation.
【作者单位】：长江勘测规划设计研究院;长江科学院水利部岩土力学与工程重点实验室;
【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)
【分类号】：TU457
【正文快照】： 中国西部地区地壳活动较为强烈,使得该地区水资源蕴藏量异常丰富的同时,也往往具有地应力网络出版时间:2016-11-4 16:56:21网络出版地址:http://www.cnki.net/kcms/detail/51.1596.T.20161104.1656.015.htmlhttp://jsuese.scu.edu.cn量级高、地质构造发育、岩体质量较差等特征

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