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震裂斜坡作为震后灾区潜在的高危地质灾害承载体分布广泛,尤其在雨季突发失稳的现象突出。针对该类灾害,以三溪村滑坡为例,通过现场详细调查,采用Seep模块探寻降雨作用下斜坡的水响应规律,并通过室内试验获取不同条件下的强度参数。在此基础上,对降雨触发型震裂斜坡变形破坏的机制模式进行归纳,参照滑坡所处实际情况建立相应的水力学模型,量化计算斜坡稳定性系数。研究表明:(1)顺层震裂斜坡灾变过程可分为原始斜坡–地震损伤–蠕变弱化–降雨触发–滑坡失稳5个演化阶段。(2)降雨是岩体形成深部裂隙、节理扩展从而切割岩体呈条块状的重要原因,同时裂隙的贯通促进了降雨入渗,导致滑带饱水软化、加速蠕变变形至失稳。(3)降雨与震后蠕变效应的耦合作用是影响坡体稳定性的主要因素,经历前期的降雨饱水软化以及同期的蠕变累计变形,最终在暴雨形成的水动力触发下失稳破坏。研究成果为降雨型震裂斜坡稳定性机制分析及工程治理提供参考。
As a potential carrier of high-risk geological disasters, the earthquake-stricken slope distributes widely as a bearing body of post-quake-hit areas, especially during the rainy season. Aiming at this kind of disasters, take Sanxi Village landslip as an example, through the on-the-spot investigation, the Seep module was used to explore the water response law of the slope under rainfall and the indoor strength parameters under different conditions were obtained. On this basis, the mechanism model of the deformation and failure of rainfall triggered shattering slope is summarized, and the corresponding hydraulic model is established with reference to the actual situation of the landslide, and the slope stability coefficient is quantitatively calculated. The results show that: (1) Stratified fissure slope catastrophe process can be divided into five stages: the original slope - earthquake damage - creep weakening - rainfall trigger - landslide instability. (2) Rainfall is an important reason for the formation of deep fractures in rock masses and joint expansion. Therefore, the penetration of fractures promotes the rainfall infiltration, which leads to the softening of the slide zone due to water saturation and accelerated creep deformation to instability. (3) Coupling effect between rainfall and post-earthquake creep effect is the main factor that affects the stability of slope. After experiencing pre-rainfall saturated water softening and cumulative creep deformation in the same period, the coupling is ultimately triggered by hydrodynamic instability of rainstorm . The research results provide a reference for the mechanism analysis and project management of rainfall-type cleave slope.