从研究岩溶地下水角度分析评价岩溶塌陷的危险性--以南宁坛洛塌陷为例

摘要

Nanning is one of the cities that have the most serious karst surface collapse in Guangxi Zhuang Autonomous Region.Karst surface collapse happened on June second,2012 mainly distributed in north-western Tanluo town.It formed 19 collapse pits and 17 ground fractures.It threatened 62 families,totally 232 people,and lead to a potential financial loss about 8.7 million.Tanluo collapse mainly formed in the zone where the loose cover is less than 15m,the cover depth of underground water is less than 20m and the underground karst strongly developed.Well developed carbonate rocks,small thickness of loose cover and complex hydrodynamic forces (rainfall,surface and underground)are necessary conditions to lead the karst collapse.Especially the underground water plays a crucial role in karst collapse.In this paper,through study on dynamic observation and karst collapse of Tanluo underground water,strong runoff zone of un-derground water has been determined,and the karst collapse risk has been analyzed and evaluated.It will have a guiding significance for hazard survey and evaluation in karst region.%南宁市是广西岩溶地面塌陷危害十分严重的城市之一。2012年6月2日突发的岩溶地面塌陷主要集中分布在坛洛镇南西方向，形成塌陷坑19个，地裂缝17条，威胁62户共232人，潜在经济损失约870万元。坛洛塌陷多形成于松散盖层厚度小于15 m，地下水位埋深小于20 m，地下岩溶强发育的区段。碳酸盐岩岩溶发育、松散盖层厚度较小和水动力条件（降水、地表水和地下水）复杂为岩溶塌陷产生的必要条件，尤以地下水的作用对岩溶塌陷的形成起至关重要的作用。通过对坛洛地下水动态观测与岩溶塌陷的调查研究确定地下水强径流带，分析评价岩溶地面塌陷的危险性，为岩溶地区的岩溶塌陷危险性勘察、评价工作提供一定指导意义。