摘要
2019年7月15日,湖南株洲市攸县樟井村发生大规模岩溶地面塌陷,严重威胁当地人民群众的生命和财产安全.为查明7·15大型岩溶地面塌陷的形成机理,通过地球物理勘探、水文地质工程地质钻探、地下水监测、水化学分析等多种手段对岩溶地面塌陷区开展了详细的调查研究,分析了该岩溶地面塌陷的发育规律及致灾因素.结果表明:7·15大型岩溶地面塌陷是由降雨主导,在地表覆盖层软化减强、岩溶气爆和渗流潜蚀效应等多种不良因素共同作用诱发的自然塌陷;地面塌陷位于断层、褶皱等构造密集发育的可溶性碳酸盐岩区域,区内岩溶强烈,广泛发育的溶洞、落水洞、泉、地下暗河等岩溶形迹为地面塌陷的形成提供了条件;7·15大型岩溶地面塌陷的形成演化可分为降雨诱发的地表覆盖层土体软化减强和封盖增荷、降雨导致地下水水位上升引发的岩溶气爆、地下水渗流潜蚀加速顶板垮塌形成土洞、土洞扩大及顶板失稳4个阶段.该研究结果可为类似地质条件地区的岩溶地面塌陷预测预报与防治提供科学依据.
Abstract
On July 15,2019,a large-scale karst ground subsidence occurred in Zhangjing Village,Youxian County,Zhuzhou City,Hunan Province,which seriously threatened the lives and property safety of local residents.In order to find out the formation mechanism of the large-scale karst ground subsidence on July 15th,the karst ground subsidence area was investigated and studied in detail by means of geophysical ex-ploration,hydrogeological engineering geological drilling,groundwater monitoring,and hydrochemical anal-ysis,and the development law and disaster causing factors of the karst ground subsidence were analyzed.The results show that the July 15 large-scale karst ground subsidence is a natural subsidence induced by rainfall,surface softening effect,cap loading effect,karst gas explosion,and seepage subduction effect.The ground subsidence is located in a soluble carbonate rock area with densely developed structures such as faults and folds.Karst in the area is strong,and the karst forms such as karst caves,sinkholes,springs and underground rivers widely developed provide the conditions for the formation of ground subsidence.The formation and evolution of large-scale karst ground subsidence can be divided into rain-induced soil soften-ing and strengthening and capping loading,rain-induced groundwater level rise and karst gas explosion,subsurface seepage erosion acceleration of roof collapse and formation of soil cave,expansion of soil cave and roof instability.The results provide a scientific basis for the prediction and prevention of karst ground subsidence in areas with similar geological conditions.
维普
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