岩溶区地下水数值模拟分析及开采方案比选

Numerical simulation analysis of groundwater in karst area and comparison of mining schemes

数值模拟是解决地下水开采评价问题的有效途径之一。为安全高效开发岩溶塌陷区地下水资源,以山东省临沂市岩溶区为例,根据水文地质调查分析,充分掌握了岩溶区地下水补给规律、运移规律、分布规律,在此基础上,选取合理模拟范围,建立数值模型,开展多方案地下水动态演化数值预测分析,据此来分析评价最优开采方案。研究结果表明:方案一岩溶塌陷危险性较高,数值观测孔水位在第1279 d、第1644 d、第2019 d和第3105 d时,水位降至灰岩顶板标高39.9 m以下,将引发岩溶塌陷风险;方案二则较安全,数值观测枯水期水位接近灰岩顶板标高,既达到地下水开发利用潜力的标准,又可保证生态地质环境安全,因此,建议采用方案二。开采过程中预警区水位应位于基岩顶板标高以下,以避免岩溶塌陷发生。本文研究结果可为类似塌陷区的科学开采提供参考。

Numerical simulation is one of the effective ways to solve the problem of groundwater exploitation evaluation.In order to develop groundwater resources in karst collapse areas with a safe and efficient way,takes the karst area of Linyi City,Shandong Province as an example,and fully understands the law of groundwater recharge,migration and distribution in karst areas according to hydrogeological investigation and analysis.On this basis,a reasonable simulation range is selected,a numerical model is established,and a numerical prediction analysis of multi-scheme groundwater dynamic evolution is carried out,based on which the optimal mining scheme is analyzed and evaluated.The results show that in scheme 1,the risk of karst collapse is relatively high.The water level of the numerical observation hole drops below 39.9 m on the 1279th day,1644th day,2019th day and 3105th day,which will lead to the risk of karst collapse.The scheme 2 is safer.The water level in the dry period is close to the elevation of limestone roof,which not only meets the standard of groundwater exploitation and utilization potential,but also ensures the safety of ecological geological environment,therefore,scheme 2 is recommended.In the mining process,the water level in the warning area should be below the elevation of bedrock roof to avoid karst collapse.This paper can provide reference for scientific mining of similar collapse areas.