地层倾角及脆韧性结构差异对滑坡变形演化的控制——来自物理模拟结果的启示

Control of formation differences of dip-angle and brittle-ductile structure on deformation evolution of landslide:insights from physical modeling

贵州省境内滑坡地质灾害分布范围广、频率高,已引起人们的极大关注。根据贵州省境内典型的滑坡灾害变形特征,研究其滑动机制对理解滑坡的形成和预警滑坡灾害发生具有十分重要的意义。为此,根据对黔西、黔北野外滑坡地质特征的观察和分析总结,设计了6组不同的地层倾角和脆-韧性层厚度组合差异的沙箱模型对滑坡的演化机制进行模拟试验,并与实际滑坡变形特征进行了对比。研究结果表明:地层的倾角和脆-韧性层厚度对滑坡的演化具有明显的控制作用;在较小地层倾角条件下主要是形成蠕滑,而且形成的断裂特征具有较大的差异;滑坡演化的扩展时序为前缘拉张-后缘拉张-中部剪断-前缘挤压-坡体缓慢蠕滑-坡体停止滑动;研究结果与晴隆县滑坡变形特征具有较好的相似性。

The geological disasters of landslides in Guizhou Province have a wide range of distribution and high frequency, and they have always received widespread attention.Therefore, based on the typical landslide deformation characteristics in Guizhou Province, studying its sliding mechanism is of great significance for understanding landslide formation and early warning of landslides.For this reason, based on the geological observation and formation characteristics of the field landslide of the western and northern Guizhou Province, this paper designed 6 sets of sandbox models with different combinations of stratum dip and brittle-ductile layer thickness.Results showed that the dip angle of the formation and the thickness of the brittle-ductile layer had obvious control effects on evolution of the landslide.It further revealed that creep was mainly formed under the condition of low stratum dip, and there were large differences in the distribution of fracture characteristics.The studies showed that the sequence of landslide evolution was to stretch and crack at the front edge-then stretch and crack at the back edge-shear in the middle-then squeeze at the front edge-and finally slowly creep and stop sliding.Results of this test are compared with the landslides in Qinglong County, and they have good similarities.