锦屏一级水电站左岸Ⅳ#-Ⅵ#山梁稳定性分析

Study of the stability analysis and three dimensional numerical simulation of #Ⅳ～#Ⅵ ridges in left bank at Jingping First Hydropower Station

锦屏Ⅰ级水电站左岸Ⅳ#～Ⅵ#山梁发育较多的深裂缝,分布有断层F2、F5、F9,这些断层、深裂缝在空间上交切组合形成了巨大的潜在不稳定块体,其在开挖及泄洪雨雾条件下的稳定性问题备受关注。在大量野外地质调查的基础上,总结了岩体裂隙分布特征及其对稳定性的影响,分析了Ⅳ#～Ⅵ#山梁在泄洪雨雾条件下整体及浅表部的变形失稳模式。在此基础上,运用三维数值模拟方法,分析Ⅳ#～Ⅵ#山梁在边坡开挖过程中地应力的变化情况,尤其是拉应力的分布范围,以此分析开挖对边坡稳定性的影响,可见开挖对山梁整体的应力分布未见明显影响,对边坡整体稳定性影响不大。运用FLAC3D软件模拟泄洪雨雾时水文地质条件改变情况下的Ⅳ#～Ⅵ#山梁变形情况,并进行了参数变化及地下水位变化的敏感性分析。参数变化分析结果表明,与地下水位变化相比较,前者边坡稳定性的影响更明显。

At Ⅳ#-Ⅵ# ridges in the left bank slope of Jingping First Hydropower Station, there are numbers of deep cracks and faults, such as F2, F5 and F9, which result in huge latent instable block in this area. So the stability of huge block becomes an important problem under the conditions of excavation and flood discharge. The cracks＇ distribution character and the influence on slope＇s stability are summarized; and the deformation model of Ⅳ#-Ⅵ# ridges under the condition of flood discharge is analyzed based on plentiful geologic investigation data. Additionally, the change of stress, especially the zone of tension stress is analyzed at the course of excavation by means of three-dimensional numerical simulation, in which the influence of excavation on slope stability is studied. It is the conclusion that there is no evidence difference to stress and whole stability of the ridges after excavation. On the other hand, the deformation of Ⅳ#-Ⅵ# ridges is analyzed and computed under the changed hydrogeological geology condition by FLAC3D. The calculation based on parameter and water table sensitivity indicates that the whole slope＇s stability is more sensitive to rock mass parameters than different water table.