基于大型物理模型试验的强降雨诱发全风化花岗岩滑坡失稳分析

随着极端天气的增多,极端强降雨诱发滑坡对人民生命财产安全造成重大威胁。以典型强烈风化花岗岩地区青岛崂山的7.23返岭前滑坡为实例,基于相似准则,采用大型滑坡模型试验箱,开展了3组不同极端降雨条件下的室内模型试验,分析了不同降雨强度条件下边坡对降雨入渗的响应规律、边坡变形过程与破坏模式,总结了强烈风化地区极端降雨诱发花岗岩类滑坡的诱发机理与降雨成灾过程。结果表明：(1)降雨诱发全风化花岗岩滑坡经历了浸润侵蚀、表层变形、破坏加深和整体失稳4个阶段,坡体呈现“片状溜滑”特征;(2)降雨强度越大,降雨入渗速率越高,土压力、孔隙水压力和含水率变化越快,滞后效应越弱;(3)坡体变形破坏与降雨入渗具有一定的空间分布规律,研究成果可为强烈风化花岗岩地区的滑坡预警与治理提供参考。

Analysis of Landslide Instability of Weathered Granite Induced by Heavy Rainfall based on Large-scale Physical Model Test

With the increase of extreme weather, landslides induced by extreme heavy rainfall pose a major threat to the safety of people''s lives and property. Taking the 7.23 Fanling landslide in Laoshan, Qingdao, a typical strongly weathered granite area, as an example, based on the similarity criterion, three groups of indoor model tests under different extreme rainfall conditions were carried out using a large landslide model test box, and the response law of the slope to rainfall infiltration under different rainfall intensity conditions, slope deformation process and failure mode were analyzed, The inducing mechanism and rainfall disaster process of granite landslide induced by extreme rainfall in strongly weathered areas are summarized. The results show that: (1) The completely weathered granite landslide induced by rainfall has experienced four stages, namely, infiltration erosion, surface deformation, damage deepening and overall instability, and the slope is characterized by "sheet slip". (2) The greater the rainfall intensity, the higher the rainfall infiltration rate, the faster the change of soil pressure, pore water pressure and water content, and the weaker the hysteresis effect. (3) There is a certain spatial distribution law between slope deformation and damage and rainfall infiltration, and the research results can provide reference for landslide warning and treatment in strongly weathered granite areas.