覆盖型岩溶平原区岩溶塌陷脆弱性和开发岩溶地下水安全性评价——以广西黎塘镇为例

Assessment of the vulnerability to sinkhole and safety of groundwater exploitation in covered karst plain——A case study in Litang town

黎塘研究区塌陷脆弱性较高,为科学地开发该区的岩溶地下水,以满足工农业生产、生活需要,本文针对黎塘镇塌陷的主控触发因素为岩溶地下水动态变化这一特点,采用现场实时监测岩溶地下水动态变化特征和室内塌陷模拟试验相结合的方法,将监测结果与当地塌陷的临界条件进行对比来确定开发岩溶地下水的安全性。结果表明,在当前开采条件下,塌陷脆弱性分区与稳定分区并非完全重合:部分高脆弱和较高脆弱区,在目前开采条件下仍处于稳定状态,部分低脆弱区则处于危险状态,并为研究区十多年来塌陷的发育、分布特征所支持印证。据此认为,在塌陷脆弱性较高的地区未必就需要绝对禁止对岩溶地下水的开发,地下水的开发应以不增加当地塌陷的频率、加剧当地岩溶塌陷的危害为前提。

Vulnerability to sinkhole is relatively high in Litang. In order to scientifically exploiting karst groundwater to meet the need of industry, agriculture and daily life, the paper discusses the safety of groundwater exploitation. Since the main triggering factor of sinkhole in Litang is the regime of groundwater, the safety of groundwater exploitation is determined by both field monitor to the regime of groundwater and indoor experiment, and then comparing the monitor result with the critical condition obtained by the experiment. The result shows that the sinkhole vulnerability ranks are not entirely coincident with the stable status under the current exploiting condition. Some areas with high and relatively high vulnerability are still in the stable status and some low vulnerability areas are in a state of dangerous, which is mostly in line with the development and distribution characteristics of the sinkholes formed in more than a decade. For this reason, it is unnecessary to completely forbid karst groundwater exploitation in areas with relatively high sinkhole vulnerability. The precondition of the exploitation is not to increase sinkhole frequency and aggravate sinkhole hazard.