| Karst collapse is one of the main types of geological disasters that can occur during urbanization in karst areas,and has the characteristics of seriousness,concealment,suddenness and mass occurrence.A large area of karst strata is distributed in the Zhongqiao area of Qixia City,Shandong Province.The karst development is relatively strong,groundwater overexploitation is serious,and karst collapse occurs repeatedly,which brings greater danger and impact to the lives of local people.Therefore,this article chooses this area for karst collapse research.Based on the karst development characteristics and karst collapse formation conditions in the study area,the genesis mechanism of karst collapse in this area was determined.Based on the GMS program,a groundwater flow model was established with the actual hydrogeological conditions in the Zhongqiao area of Qixia City.This model is used to change the amount of groundwater mining in the mining area of??the study area,compare the relative position of groundwater level with the bedrock surface and the actual karst development under different mining volumes,and combine previous experience to analyze and predict karst collapse.In the study area,the groundwater level is mainly affected by the mining area.The model sets multiple dredging levels(15m,10 m,5m,0m,-5m,-10m)to the pit under the conditions of flat water years to predict the groundwater flow field at different mining volumes.Based on the data in the study area and previous experience,it is concluded that the karst collapse is prone to occur between the groundwater level and the relative position of the bedrock surface 2m.Comparing the groundwater flow field maps and the bedrock surface maps of the study area at different extraction volumes,the areas where karst collapse may occur are obtained.The analysis shows that when the groundwater level changes near the bedrock surface,it has an important impact on the occurrence of karst collapse. |
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