石泉水电站陡高边坡崩塌机理分析及加固设计

COLLAPSE MECHANISM ANALYSIS OF STEEP-HIGH ROCK SLOPE OF SHIQUAN HYDROPOWER STATION AND REINFORCEMENT DESIGN

石泉水电站二期工程发电厂房为岸边式,机坑开挖深度约42 m。在机坑开挖过程中,边坡表层发生了2次崩塌性破坏,在厂房和边坡之间形成一个“月牙”形空缺。根据崩塌后揭露的地质构造特性,分析了高边坡的崩塌机理。在此基础上,拟定加固方案,并用极限平衡法优化出合理的锚索锚固力,用二维接触非线性有限元分析边坡岩体与混凝土框架之间的相互作用;根据数值仿真计算结果,作出了在“月牙”形空缺处修建混凝土框架结构的边坡综合治理加固方案,其目的是利用混凝土框架结构的适度变形所产生的弹性抗力来增加边坡坡脚的稳定性;实践已证明,此方案的实施,不仅提高了边坡岩体的安全度,而且获得了良好的经济效益。

The powerhouse of the Shiquan hydropower station is located near the river bank. The turbine pit excavation depth is about 42 m. During excavation,collapse of surface layers of the rock slope happened twice,and a crescent open space was formed between the powerhouse and the rock slope. According to geological structure characteristics of the collapse exposure,the collapse mechanism of the high slope was analyzed. On this basis,a reinforcement scheme was designed. Required force for the pre-stressed cable bolt was optimized by the limit equilibrium computation. Interactions between the slope and concrete frame were analyzed by a 2D contact-nonlinear FEM. Based on the numerical simulation results,a comprehensive treatment and reinforcement scheme of building concrete frame in the crescent open space was worked out. The idea is to utilize the elastic resistance generated from the moderate distortion of the concrete frame to increase the stability of the slope foot. The practical cases show that this scheme not only increases the safety degree of the slope,but also provides favorable economical benefit.