川南红层区黄子树滑坡形成过程与运动特征

Mechanism and kinematic characteristics of Huangzishu Landslide in the red mudstone of southern Sichuan

川南红层区褶皱强烈、岩性复杂、断裂发育,加之地形条件差,在雨季极易形成滑坡灾害。本文以川南红层区的黄子树滑坡为例,通过工程地质测绘和钻孔勘探,对滑坡发育特征和形成机制进行了研究,并在此基础上,运用二维离散元模拟技术对滑坡进行数值模拟,还原整个灾变过程,得出了滑体不同部位的位移时程曲线和速度时程曲线,取得如下认识:滑坡是特殊岩性组合与降雨或地震共同作用形成,整个形成演化过程可以分为前缘蠕滑阶段、整体滑移阶段和碰撞堆积阶段,滑体最大滑移量达105 m,前缘滑体速度远大于后缘,最大速度达6.5 m/s,滑坡具有剧动启程效应和滞后效应,滑体速度在达到峰值后呈波浪式逐级减缓。

In the Red-bed of southern Sichuan,strong folds,complex lithology and fracture development,combined with poor terrain conditions,are easy to form landslide disaster in the rainy season.Taking the Huangzishu Landslide in the red-bed region of southern Sichuan as an example,this paper studies the development characteristics and formation mechanism of landslide through engineering geological mapping and borehole exploration.On this basis,the numerical simulation of landslide is carried out by using the two-dimensional discrete element simulation technology to restore the whole catastrophe process,and the displacement time-history curves and velocity time-history curves of different parts of the landslide are obtained.Conclusions are as follows.Landslides are formed by the combination of special lithology and rainfall or earthquake.The whole process of formation and evolution can be divided into leading edge creeping phase,overall slipping phase,and collisional accumulation phase.The maximum slip of the slider is up to 105 m and the leading edge slider speed is much larger than the trailing edge,whose maximum speed is 6.5 m/s.Besides,the landslide has a dramatic departure effect and a hysteresis effect,and the velocity of the slider slows down gradually after reaching the peak.