西南岩溶山区复合水动力场滑坡影响模式——以关岭县大寨滑坡为例  

Impact model of landslide with complex hydrodynamic field in karst mountain areas of southwest China:a case study of the Dazhai landslide in Guanling County

作　　者：易连兴[1] YI Lianxing(Institute of Karst of Geology,CAGS/Key Laboratory of Karst Dynamics,Ministry of Natural Resources,Guilin,Guangxi 541004,China)

机构地区：[1]中国地质科学院岩溶地质研究所/自然资源部广西岩溶动力学重点实验室,广西桂林541004

出　　处：《水文地质工程地质》2020年第4期43-50,共8页Hydrogeology & Engineering Geology

基　　金：国家重点研发计划项目(2018YFC1504800)。

摘　　要：岩溶地下水对我国西南岩溶石山地区特大型滑坡频发具有重要影响,因此,岩溶地下水的赋存规律及在其影响下的滑坡成灾模式成为一个亟待研究的科学问题。文章以贵州省关岭县岗乌镇大寨村大寨滑坡为例,基于野外调查,结合水动力场、水化学数据、暴雨数据等进行综合分析,取得以下成果和认识:(1)划分出大寨滑坡区地下分水岭,圈定了影响大寨滑坡的灰岩区和碎屑岩区,面积分别为0.93,0.30 km2;(2)滑坡当日暴雨集中在6—12时,后缘区域岩溶管道水对大寨滑坡滞后暴雨2 h启动起到主要控制作用;(3)滑坡区碎屑岩以及后缘灰岩接受了百年一遇的强降水的入渗补给后,在各自内部形成高压水动力场;在基岩裂隙水、岩溶管道水两种水动力场及岩层自身重力的共同作用下,潜在软弱结构面上的岩层失稳进而发生滑坡。由此建立了基岩裂隙水和岩溶管道水复合水动力场对滑坡的影响模式,并提出一种复合水动力场耦合方法。Groundwater in karst aquifers has an important effect on the large landslides frequently occurring in the karst mountain areas in southwest China.The storage rule of karst groundwater and its impact model on landslide disasters have become a scientific problem to be studied urgently.At 14:00 on June 28,2010,a huge landslide disaster occurred at Dazhai near Gangwu Town in Guanling County of Guizhou Province,resulting in dozens of deaths and a large number of residential damage.This paper takes the Dazhai landslide as an example,and the field investigations,combining with hydrodynamic field analysis,hydrochemical analysis,rainstorm data analysis and comprehensive analysis are carried out.The research results show that(1)the underground watershed of the Dazhai landslide area is divided,and the area of limestone and clastic-rock affecting the Dazhai landslide is delineated as 0.93 and 0.30 km2,respectively;(2)The heavy rain on the day of the landslide mainly occurred at 6:00—12:00,and it is considered that the karst conduit water in the trailing edge area plays a major role in controlling the start of the Dazhai landslide 2 hours after the heavy rain.(3)After the recharge of once-in-100-years heavy precipitation,the high-pressure hydrodynamic field was formed respectively in clastic-rocks and trailing edge limestones of the landslide area.Under the combined action of the two hydrodynamic fields(bedrock fissure water and karst conduit water)and the gravity of the rock-layer,rock formation instability on potentially weak structural surfaces was caused and the formation of this landslide was eventually occured.This paper establishes the landslide impact model of the compound hydrodynamic field of bedrock fissure water and karst conduit water,and may provide a method of coupling the compound hydrodynamic field.

关 键 词：大寨滑坡 岩溶石山 岩溶管道水 复合水动力场 暴雨延迟效应 

分 类 号：P642.2[天文地球—工程地质学]