新疆叶城“7·6”滑坡泥石流灾害调查与形成机理研究

摘要

2016年7月6日晨0时40分左右，新疆喀什地区叶城县柯克亚乡六村发生特大滑坡泥石流灾害，造成重大人员伤亡和财产损失。本研究采用地面调查、访问和遥感解译方法，从滑坡、泥石流形成的地形地貌、地层岩性和水文气象条件着手，分析了滑坡特征与成因，泥石流形成条件、灾害链过程与致灾机理，并对未来本区滑坡泥石流的发展趋势进行了预测。现场调查表明：（1）位于西昆仑山北坡中高山区的六村与七村毗邻区域，在6日凌晨发生的大暴雨，触发了38处群发性浅层黄土滑坡，属蠕滑－拉裂机制，且部分大滑坡表现为远程滑坡－泥流特征；（2）这些滑坡体堆积在“V”形沟谷中形成堰塞坝，其中六村上游发育15处滑坡和2个滑坡堰塞坝，在持续降水和小型沟谷泥石流的作用下，滑坡坝发生串联式溃决而形成堵溃型泥石流，冲毁六村居民区和道路；（3）同时，该毗邻区域两侧存在超过227处的黄土滑坡变形体，未来在区域气候由暖干转向暖湿条件下，强降雨的极端气候事件会增多，若遭遇强降雨，研究区仍然会爆发滑坡－堰塞坝－溃决泥石流模式的灾害，其规模可能比“7·6”事件还大。建议深化本区浅层黄土滑坡变形机理、临界雨量及泥流运动机理等方面的深入研究，同时加强滑坡泥石流的监测和预测研究。%In early morning of July 6,2016,there took place a large debris flow disaster in Liucun,Yecheng county of Xinjiang.The event made serious villagers death and property loss.The paper,adopting the methods of in-situ investigation, witness interviewing and remote sensing explanation, based on the topography and morphology,lithologies and geological structure,as well as the climate and hydrology,analyzes the characteristics and formation of the landslides,the conditions and hazard chains and disaster mechanism of the debris flow.It also predicts the trend of landslide /debris flow in this area.The in-situ investigation shows(1 )in the adjacent area between Liucun and Qichun of the northern slope of West Kunlun Mountains,38 landslides were triggered by a rainstorm in that day.The landslides are shallow,loess type with the mechanism of Creeping-Tension,and some big landslides have the characteristics of long-runout.(2)the landslide debris accumulated in the gully of “V-shape”to form dams.Among which,there were 15 landslides and 2 dams in the upstream of Liuchun.Under the action of rainfall and small debris flow upwards,the dams are outbreak to form debris flow.(3)there exist more than 227 loess slopes under deforming in the both sides of “V-shape”gully,in the condition of climate change and the increasing of extremely climate events,those slopes would take place similar landslides.The size could be much larger than that of this time.At last,it is suggested to promote advanced research to the mechanism of the shallow loess landslides,the critical rainfall strength,and the movement of mud flow,and strengthen the study of the monitoring,prediction and early alarming of such landslide-debris flow geohazard chains.