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中国西南地区在建的猴子岩水电站地下厂房,具有高边墙大跨度的特点。且位于高地应力区,实测最大主应力值高达36.43 MPa。地下厂房区域的灰岩坚硬完整、脆性程度高,具备高储能条件,在施工开挖扰动因素下有可能发生岩爆动力地质灾害。依照岩爆综合预测研究的思路,结合前期猴子岩水电站地下洞室群岩爆倾向性研究,开展岩爆趋势预测研究。建立三维有限元计算模型,根据实测地应力资料进行初始地应力场拟合,模拟猴子岩水电站地下洞室群分步开挖过程,选择王兰生二郎山隧道判据进行岩爆趋势预测。通过分析主厂房、主变室、尾调室三大洞室分步开挖过程中的岩爆趋势预测情况可知:猴子岩地下洞室群开挖过程中主要发生轻微岩爆,个别区域可能发生中等岩爆,与实际情况相比仍有一定差异。同时,归纳已有的多种岩爆预测判据,结合大量工程资料,对岩爆判据的适用性进行系统探讨。研究表明,单一判据在工程中有较大的局限性,预测结果与实际情况有较大偏差;而五因素综合判据则能较准确地反映工程的岩爆情况。
The underground powerhouse of the monkey rock hydropower station under construction in southwest China has the characteristics of a long span of high-side walls. And located in the high stress area, the measured maximum principal stress value up to 36.43 MPa. The limestone in the underground plant area is hard and intact, with a high degree of brittleness and high energy storage conditions. Rockburst dynamic geohazards may occur under disturbance factors of excavation. According to the research thought of rockburst, combined with the research on the rockburst tendency of the underground caverns at the former stage of the Houzhanyan Hydropower Station, the rockburst tendency prediction is studied. The three-dimensional finite element model was established. According to the measured geostress data, the initial geostress field was fitted to simulate the excavation process of the underground caverns at the Houzhipin Hydropower Station. The Rock Burst Tendency was selected based on the Wanglangsheng Erlangshan Tunnel Criterion. By analyzing the predictions of rockburst trends during the step-by-step excavation of the three main caverns in the main workshop, main transformer chamber and tail transfer chamber, we can see that slight rock burst mainly occurs in the excavation of the underground caverns in the monkey rock and may occur in some areas Rock burst, compared with the actual situation is still some differences. At the same time, the existing predictions of rockburst are summed up. Based on a large amount of engineering data, the applicability of rockburst criterion is discussed systematically. The research shows that the single criterion has more limitations in the project, and the prediction result has a big deviation from the actual situation. The five-factor comprehensive criterion can more accurately reflect the rockburst of the project.