具有复杂变形特征的倾倒变形岩体分带及稳定性

倾倒变形是河谷地区层状岩质边坡一种典型的变形破坏方式。星光三组倾倒变形岩体位于溪洛渡水电站库区,变形体范围内地层从寒武系筇竹寺组至志留系连续分布,碎屑岩与碳酸盐岩表现出复杂的倾倒变形特征。为全面评价变形体的稳定性,借鉴《水力发电工程地质勘察规范》,建立倾倒变形分带标准并确定各带的岩体质量级别;在此基础上,综合各类岩体的岩石室内试验成果和坝基岩体力学参数经验值,采用工程类比方法确定出各变形带不同岩性的物理力学参数;选取岸坡强变形区,运用极限平衡方法进行稳定性计算,其结果与蓄水后岸坡表现出的变形迹象吻合。研究结果对倾倒变形岩体的稳定性评价有一定的借鉴意义。

Zoning and stability analysis for toppling deformation rock mass with complex deformation characteristics

Toppling deformation is a typical deformation failure mode of layered rocky slopes in river valley. Xingguangsanzu toppling rock mass is located in the reservoir area of Xiluodu Hydropower Station. The strata of the toppling rock mass are distributed continuously from the Cambrian Qiongzhusi Formation to the Silurian, and the clastic rocks and carbonate rocks show complex toppling deformation characteristics. In order to comprehensively evaluate the stability of the toppling rock mass, by referring to “Code for hydropower engineering geological investigation”, the toppling deformation zoning standard was established and the rock mass quality grade of various deformation zone was determined. Based on this, combined with various laboratory test results of rock and empirical value of dam foundation rock mechanics parameters, the physical and mechanical parameters of different lithology in various deformation zones were determined by engineering analogy method. Aiming at the strong deformed area of the toppling rock mass, the stability was calculated by the limit equilibrium method, and the results were in agreement with the signs of deformation after the water storage operation. The research can provide reference for stability evaluation of toppling deformed rock masses.