白鹤滩水电站岩质边坡微震活动特征研究

发布时间：2018-07-31 15:07

【摘要】：白鹤滩水电站左岸边坡高陡,应力条件复杂,存在LS_(331)、LS_(337)、LS_(3319)层内错动带,F17断层等软弱结构面,施工期和运营期安全问题十分突出。为评价其左岸边坡开挖稳定性,利用微震监测系统对边坡微震活动进行实时监测,并分析微震活动的时空以及震级分布,揭示岩质边坡开挖扰动下的微震活动特性及其施工响应特征。结果表明:开挖强度越大,边坡损伤越大,微震活动越活跃;爆破后0.5h内应力急剧调整,微震活动频繁;震级分布在-1.6~0.4之间,爆破开挖诱发大量震级小能量低的微震事件,诱发边坡的渐进损伤;软弱结构面是微震事件的主要活动区域,具有发生破坏变形的可能性;左岸边坡岩石破裂以复合型破坏和剪切破坏为主,伴随少量拉伸破坏。该研究可为工程后续开挖和支护提供参考,为同类微震活动特性分析提供一定的借鉴。
[Abstract]:The left bank slope of Baihetan Hydropower Station is high and steep, and the stress condition is complex. There exists weak structural plane such as fault F17 in the fault zone of LS331and LS3319 layer. The safety problems during construction and operation are very prominent. In order to evaluate the stability of the slope excavation on the left bank, the microseismic monitoring system is used to monitor the microseismic activity of the slope in real time, and the time and space of the microseismic activity and the magnitude distribution of the microseismic activity are analyzed. The characteristics of microseismic activity and construction response of rock slope under excavation disturbance are revealed. The results show that the greater the excavation intensity, the greater the slope damage, and the more active the microseismic activity, the sharp adjustment of stress within 0.5 h after blasting, the frequent microseismic activity, the magnitude distribution between -1.6 and 0.4, and the large number of microearthquakes with low magnitude and low energy induced by blasting excavation. The soft structural plane is the main active area of microseismic events, which has the possibility of failure and deformation; the failure of rock on the left bank is dominated by composite failure and shear failure, accompanied by a small amount of tensile failure. The research can provide reference for engineering excavation and support, and for the analysis of similar microseismic characteristics.
【作者单位】：四川大学水力学与山区河流开发保护国家重点实验室;
【基金】：国家自然科学基金面上项目(51679158) 国家重点基础研究发展计划(973计划)项目(2015CB057903)资助
【分类号】：TV223

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