甘肃天水红旗山黄土滑坡群成因及稳定性分析

Genetic mechanism and stability analysis of loess landslides group in Tianshui Hongqishan, Gansu Province

天水市位于西秦岭北缘断裂带,区内活动断裂发育,历史上强震频发,诱发了大量黄土滑坡。基于对天水市北山地震滑坡群的野外调查,研究了地震滑坡变形破坏特征;以红旗山滑坡群为典型案例,结合室内测试结果,剖析了红旗山滑坡的变形破坏机制;利用FLAC3D模拟分析了现今红旗山滑坡的稳定性。研究结果表明:天水北山滑坡群由地震作用诱发;红旗山滑坡包含两个主滑动带,历史上经历了3期以上变形活动,演化过程复杂,属地震-降雨耦合型滑坡。现今红旗山滑坡体在天然状态下相对稳定,如遇强震作用将造成坡体内部塑性区贯通,斜坡顶部岩土体将发生滑移。这一研究成果可为潜在强震区地震滑坡的变形机理及防灾减灾提供依据。

Tianshui is located in the faulted zone at the northern edge of the West Qinling Mountain.The active faults in the area are well developed.According to historical record,the earthquakes used to happen frequently.A large number of loess landslides have been induced in this area.Based on field investigation of the north mountains landslide group in Tianshui,the authors studied the deformation and failure characteristics of the earthquake landslide.Taking Hongqishan landslide as a typical case,combined with laboratory test results,the authors analyzed deformation mechanism of Hongqishan landslide,and then applied FLAC3D to simulate the stability of Hongqishan landslide.The results show that the north mountain landslide group in Tianshui is induced by earthquake action;Hongqishan landslide contains two main slip belts,and it has experienced more than3deformation activities in history.Its evolution process is complicated and belongs to earthquake-rainfall coupled landslide;Nowadays,the Hongqishan landslide is relatively stable under the natural condition.If a strong earthquake occurs,it will cause a breakthrough of the plastic zone inside the slope,and the soil on the top of the slope will slip.The research results can provide a basis for the deformation mechanism and disaster prevention of the earthquake landslide in the potential strong earthquake area.