高地应力条件下锦屏一级主厂房围岩松弛深度形成规律和支护时机研究

发布时间：2018-03-14 17:38

本文选题：锦屏一级水电站　切入点：高地应力　出处：《工程地质学报》2016年05期 　论文类型：期刊论文

【摘要】：近年来我国西部已建成发电或正在建设的一批大型、特大型水电工程,其地下洞室群多处于高山峡谷地区,地质条件复杂、地应力较高。受高地应力影响,施工期洞室群围岩易出现不同程度的变形破坏,并常常导致超常规深度的围岩松弛。本文结合锦屏一级水电站主厂房围岩松弛长期物探检测成果,系统分析了围岩松弛深度的形成、发展和演化趋势,再采用数值分析手段,通过围岩位移、塑性区发展趋势来研究最佳支护时机,研究表明:高地应力地区厂房轴线宜尽量与最大主应力σ1方向平行,能有效减小时效变形导致的不同部位不同程度的围岩松弛;洞室分层开挖时,围岩松弛深度的80%在本层开挖后间隔2~3层时形成;相比开挖后滞后支护,及时支护围岩位移量、塑性区明显较小,因此及时支护为最佳支护时机。研究成果对高地应力条件下大型地下洞室轴线选择、支护设计、支护时机选择具有参考意义。
[Abstract]:In recent years, a number of large and super large hydropower projects have been built or are under construction in the west of China. The underground caverns are mostly located in the high mountain and canyon areas. The geological conditions are complex, the ground stress is high, and the underground stress is affected by the high ground stress. During the construction period, the surrounding rock of the cavern group is liable to be deformed and destroyed to varying degrees, which often leads to the relaxation of the surrounding rock of the abnormal depth. This paper combines with the long-term geophysical exploration results of the relaxation of the surrounding rock of the main powerhouse of the Jinping Hydropower Station. The formation, development and evolution of the relaxation depth of surrounding rock are analyzed systematically, and then the optimum supporting time is studied by numerical analysis, through the development trend of surrounding rock displacement and plastic zone. The results show that the axis of powerhouse in high ground stress area should be parallel to the maximum principal stress 蟽 1 as far as possible, which can effectively reduce the relaxation of surrounding rock in different parts caused by aging deformation. 80% of the relaxation depth of surrounding rock is formed at the interval of 2 ~ 3 layers after excavation, and the displacement of surrounding rock in time is smaller than that of delayed support after excavation, and the plastic zone is obviously smaller. Therefore, timely support is the best time of support. The research results have reference significance for the selection of axis, support design and timing of support for large underground cavern under high ground stress.
【作者单位】：中国电建集团成都勘测设计研究院有限公司;长江科学院水利部岩土力学与工程重点实验室;
【基金】：国家自然科学基金项目(51379022;51539002)资助
【分类号】：TV223

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