白鹤滩电站左岸强卸荷区边坡稳定试验研究

Stability of the Left Bank High Slope in Strong Unloading Area of Baihetan Hydropower Station

针对岩质高边坡的稳定问题,提出了基于变温相似材料的降强法与倾斜抬升超载法相结合的综合法模型试验方法,建立了边坡稳定综合法试验安全评价方法,并针对白鹤滩电站左岸强卸荷区高边坡的稳定问题开展试验研究。通过典型剖面及卸荷区边坡的2个模型试验,获得了边坡在底滑面降强后的变形特性和破坏机理,揭示了缓倾结构面是影响白鹤滩边坡稳定的控制性因素,其失稳模式为滑移—拉裂的块体滑动破坏。试验结果表明,在底滑面前缘区域布置混凝土置换洞,可有效增强底滑面抗剪能力、减小边坡变形、阻止滑块形成,加固后的边坡稳定安全系数为KSC=1.42~1.58。研究成果为白鹤滩边坡工程的安全评价和加固处理提供了科学依据,同时也为类似边坡工程提供参考。

A comprehensive model test method is proposed to study the stability of rock slope. The comprehensive method involves the strength reduction method based on temperature-dependent similar material and the overloading method by inclined lifting. Corresponding safety evaluation method for slope stability is also established. The left bank high slope in strong unloading area at Baihetan Hydropower Station is taken as a case study. Through two model tests of a typical section and the whole slope in strong unloading area,the deformation features and failure mechanism after reducing the strength of bottom sliding surfaces are obtained. Results reveal that the gently-inclined structural planes are dominant factors of slope stability; the failure mode is block sliding with sliding-tension fracturing. Moreover,results also suggest that concrete replacement plugs in the front area of bottom sliding surface is an effective measure of enhancing the shear capacity of bottom sliding surface,reducing slope deformation and preventing blocks from sliding. The safety factor of reinforced slope is between 1.42 and 1.58. The research results provide an important scientific basis for the slope safety evaluation and the reinforcement treatment of Baihetan Hydropower Station,and also offer reference for similar slope projects.