Formation process of cover collapse sinkholes related to groundwater level decline in karst areas  

作　　者：LIU Xingzong CHEN Hongkai GONG Bin JIANG Guanghui WANG Jintao 

机构地区：[1]School of Civil Engineering,Ludong University,Yantai 264025,China [2]School of Geographical Sciences,China West Normal University,Nanchong 637001,China [3]College of Engineering,Design and Physical Sciences,Brunel University London,London UB83PH,UK

出　　处：《Journal of Mountain Science》2024年第11期3832-3846,共15页山地科学学报（英文）

基　　金：supported by the Natural Science Foundation of Shandong Province,China(Grant No.ZR2020QE110);the National Natural Science Foundation of China,China(Grant No.52104089).

摘　　要：The decline in groundwater level is a key factor contributing to cover collapse in karst areas.In this study,the model tests and numerical simulations are conducted to reveal the breeding process and formation mechanism of cover collapse sinkholes caused by the decline of groundwater level in karst area.Firstly,the model tests confirm that the decline of groundwater level generates negative pressure at the lower edge of overlying soil.The negative pressure experiences four distinct phases during the groundwater drawdown process:rapid rise,slow decline,rapid decline,and gradual dissipation.The maximum negative pressure is influenced by the particle size distribution of the overlying soil.Then,the numerical simulations are carried out to investigate the change process of negative pressure caused by the loss of fillers in karst pipe.The simulated results indicate that the rate of groundwater decline and the thickness and initial void ratio of the overlying soil can affect the maximum negative pressure.As groundwater level drops,a negative pressure zone forms underground,causing tensile failure in the surrounding soil and creating an arched soil hole,which weakens the support for the overlying soil.This phenomenon can also lead to the collapse of the overlying soil under its self-weight.Groundwater table decline in karst areas can result in both internal and surface collapses.When the overlying soil is thin,internal and surface collapses occur simultaneously.In contrast,for thick overlying soil,internal collapse happens first,followed by a layer-by-layer collapse,ultimately forming sinkholes.Finally,the breeding process and formation mechanism of the Yujiawan Reservoir sinkholes are discussed.Geological conditions and groundwater level decline significantly affect internal collapse in karst areas,requiring careful consideration from on-site engineers.

关 键 词：Cover collapse sinkhole Groundwater level decline Karst area Model test Numerical simulation 

分 类 号：P642.25[天文地球—工程地质学] P641.134[天文地球—地质矿产勘探]