某地下水封洞库围岩稳定性研究

发布时间：2018-01-31 16:05

本文关键词： 地下水封洞库岩体质量级别数值模拟围岩稳定性　出处：《西南交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：本文以某地下水封洞库为例实例,对该研究区的区域地质概况、工程地质及水文地质条件、洞库岩体质量和围岩级别等进行了探讨,并通过Phase软件在未考虑地下水的情况下,对变形体发育范围内岩体天然应力场特征进行了分析和模拟；然后,通过数值模拟分析了洞库在开挖后的应力和位移特征。主要得出了以下结论：1、根据综合分析,研究区地形起伏小、山体较完整,无崩塌、滑坡、泥石流等不良地质现象发育,对洞库围岩稳定性影响较小,初步认为该研究区适宜建库。2、根据BQ值评分法、Q系统法和T值评分法等综合评价,得出了研究区洞室围岩质量指标与深度的关系,微风化花岗岩的质量级别以II类为主,总评分T均大于65,围岩强度应力比S均大于4,评价场区微风化中细粒花岗岩为基本稳定,但不排除需要局部加固。3、洞室开挖后在无支护的条件下,围岩的应力分布重新调整,主要表现为：洞室周边最大主应力释放降低,相对于初始应力值应力释放了0.2～2.5MPa；在洞室群两侧处和边角处,压应力集中较为明显,整个洞室围岩无最大主应力拉应力区出现。同时,围岩的变形趋势表现比较明显,整体表现为有岩土内部向开挖临空方向产生位移,变形影响范围为1.5倍洞高。因此,在洞室的顶部,围岩易发生张剪破坏,造成洞顶坍塌或掉块破坏；在洞室的侧壁,围岩易发生压剪破坏,造成岩体崩裂等破坏。总之,通过本文在已有工程手段的基础上,对地下水封洞库围岩稳定性进行了分析评价,对下阶段工作具有一定指导意义。
[Abstract]:In this paper, the regional geological situation, engineering geology and hydrogeological conditions, rock mass quality and surrounding rock grade of a underground water sealing cave reservoir are discussed in this paper. The analysis and simulation of the natural stress field of rock mass in the range of deformable body are carried out by Phase software without considering the groundwater. Then, the stress and displacement characteristics of the cavern after excavation are analyzed by numerical simulation. The following conclusions are drawn: 1. According to the comprehensive analysis, the topography of the study area is small, the mountain body is relatively complete, no collapse, landslide. The development of debris flow and other bad geological phenomena has little influence on the stability of the surrounding rock of the cave reservoir. It is preliminarily considered that the study area is suitable for building reservoir .2. the comprehensive evaluation is based on the Q-system method and T-value scoring method. The relationship between quality index and depth of surrounding rock in the study area is obtained. The quality grade of breezy granite is mainly class II, the total score T is more than 65, and the ratio of strength and stress of surrounding rock is more than 4. The evaluation of the fine granites in the field area is basically stable, but does not rule out the need for local reinforcement. 3. After excavation, the stress distribution of surrounding rock is readjusted under the condition of no support. The main results are as follows: the maximum principal stress release of the surrounding cavern is reduced, and the maximum principal stress release is 0.2 ~ 2.5 MPa relative to the initial stress value; At both sides and corners of the cavern group, the compressive stress concentration is obvious, and no maximum principal stress tensile stress zone appears in the surrounding rock of the whole cavern. At the same time, the deformation trend of the surrounding rock is obvious. As a whole, the internal displacement of rock and soil to the direction of excavation is caused, and the influence range of deformation is 1.5 times higher. Therefore, at the top of the cavern, the surrounding rock is liable to occur tension-shear failure, which results in the collapse of the roof of the cave or the failure of the block. On the side wall of the cavern, the surrounding rock is prone to compression-shear failure, resulting in rock mass collapse and other damage. In short, based on the existing engineering means, the stability of surrounding rock of underground water sealing cavern is analyzed and evaluated. It has certain guiding significance for the next stage of work.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE822

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