摘要
以荆泉断块岩溶水系统为研究对象,通过建立地下水流模型和数学模型,旨在实现不同环境条件下岩溶塌陷预警分区,指导岩溶水资源开发利用.结果显示:在其它条件保持不变的情况下,随着降雨量的不断减小,研究区红色预警区面积不断增大,抽水井越密集的地方,越容易产生岩溶塌陷,岩溶水开采量的增加和降雨量的变化都是诱发岩溶塌陷的主要原因.建议以岩溶塌陷为约束条件,加强区内地下水开采优化控制与布局,在保证生产生活用水的前提下,降低岩溶塌陷发生概率.
Abstract
As one of the most common geological disasters in the Jingquan area,covered karst collapses mostly occurred in the dry seasons from 2015 to 2017.With the frequent occurrence of karst collapses,the sustainable development of economy and the safety of people's lives and property are threatened.Therefore,it is urgent for us to find out the current situation of karst collapses,analyze their influencing factors and distribution rules,and carry out the research on the zoning of early warning for karst collapses under different environmental conditions,in order to provide a decision-making basis for carrying out targeted prevention and control.In view of the frequent occurrence of covered karst collapses in the Jingquan area,based on the exploration data of karst collapses in this area,this study analyzes and studies the background conditions and influencing factors of collapse formation with methods such as mathematical statistics,numerical simulation and comprehensive evaluation model.Through numerical simulation and fuzzy mathematical methods,the zoning of early warning for karst collapses under different environmental conditions(rainfall frequency of 20％,50％,80％and 95％,and the increase of mining volume of 30％,50％and 70％)is studied,and targeted prevention and control measures are put forward.The research conclusions mainly include the following four aspects:(1)The aquifer system in the Jingquan area can be generalized into three aquifer groups as a whole.The first layer—the shallow aquifer group—includes pore water in the Quaternary coverage area and shallow water in the exposed bedrock area.The second layer—the weakly permeable aquifer group—includes the Quaternary clay layer and the fractured deep aquifers of Cambrian and Ordovician in a certain depth range.The third layer—the deep aquifer group—includes Ordovician aquifers of carbonate fissure karst water and Cambrian aquifers of carbonate karst water.(2)In this study,the lower boundary of the water flow system has been set at the buried depth of 200 m in the Jingquan area.The atmospheric precipitation infiltration and the lateral runoff supply of groundwater are the main supply sources of groundwater in the study area.The main discharge of groundwater in the area is the exploitation of groundwater.The exploitation amount of the water source has been obtained through monitoring data,and the scattered exploitation amount has been obtained through investigation and statistics.(3)Given that other environmental conditions remain unchanged,the area of the red-early-warning area gradually increases with the continuous reduction of precipitation,and the degree of early warning gradually decreases from southwest to northeast.The denser the pumping wells are,the likelier karst collapses occur.The increase of karst water exploitation and the change of rainfall are the main causes of karst collapses.(4)In order to prevent karst collapses in this area,we should strengthen the management of water resources and make rational use of groundwater resources.We should also strengthen the monitoring of karst collapses in the red-warning area,and adopt a variety of engineering measures to change the geological background conditions of karst collapses to the greatest extent.
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