甘肃黑方台“10·5”黄土滑坡启动及运动特征分析

The initiation and motion characteristics of the“10·5”loess landslide in the Heifangtai platform,Gansu Province

数十年的塬上大面积灌溉导致甘肃黑方台地下水位不断提升,迄今为止已有约200余起黄土滑坡发生,造成了大量伤亡,给当地居民生活和财产安全带来了巨大的影响。针对黑方台黄土滑坡启动迅速、运动速度快、影响范围广的特征,文中以2019年10月5日发生在黑方台党川村附近的一起黄土滑坡为研究对象,通过野外调研和无人机手段,获取该滑坡的发育特征和地形数据。基于Massflow软件再现了该滑坡运动全过程,最终得到堆积厚度及运动速度2个方面特征,得出以下结论:(1)“10·5”黄土滑坡体积约2.7×10^(4)m^(3),最大滑距355 m,属于小型黄土滑坡;(2)模拟结果显示,滑坡运动持续时间约45 s,最大运动速度为26 m/s,反演结果与实际情况较吻合。运动过程可分为启动加速阶段、稳定加速阶段、减速堆积阶段三个阶段;(3)对滑坡堆积厚度进行分析发现,该滑坡在主滑方向上平均厚度约0.59 m,最大堆积厚度为1.35 m,沿滑坡运动方向,堆积厚度呈现先增大后减小的趋势,堆积区最大堆积厚度为0.82 m。该研究成果可为黑方台黄土滑坡风险防控提供一定的技术支持。

Long-time diversion irrigation has led to the continuous rise of the groundwater level in the Heifangtai platform,Gansu Province.So far,more than 200 loess landslides have occurred,causing more catastrophic threats to local people and property.The loess landslides on the Heifangtai Platform were charactered by rapid initiation,fast speed and wide accumulation area.A loess landslide occurred near Dangchuan village in the Heifangtai Platform on October 5,2019.The characteristics and topographic data of the landslide were obtained by field investigation and UAV technology.We used the Massflow software to simulate the motion process of the landslide,and the deposits thickness and motion speed of the landslide are obtained.The result show that:(1)The“10·5”landslide has a volume of about 2.7×10^(4)m^(3)and a maximum sliding distance of 355 m.It is a small kind of loess landslide;(2)The motion time is about 45 s,the maximum movement speed is 26 m/s,and the inversion result is consistent with the actual situation.The landslide movement process is divided into three stages:start acce-leration→steady acceleration→deceleration accumulation;(3)It found that the average thickness and maximum accumlation thickness of the landslide in the main sliding direction were respectively 0.59 m and 1.35 m.The accumulation thickness shows a trend of increasing momently and then decreasing.The largest accumulation thickness is 0.82 m.The research results can provide related technical support for the risk prevention of the loess landslide occurred in the Heifangtai Platform.