碳酸盐岩区大型水库蓄水后地下水渗流场特征及岩溶演化趋势

GROUNDWATER SEEPAGE FIELD FEATURES AND KARST EVOLUTION TREND IN LARGE WATER_FILLED IMPOUNDING RESERVOIR IN CARBONATE ROCK REGION

碳酸盐岩区大型水库蓄水引起的地下水渗流场及岩溶环境变化的研究，既是一个工程实际问题，同时也是岩溶环境学的理论问题．以高坝洲和隔河岩水库为例，运用数值模拟方法模拟了水库蓄水前后地下水渗流场的平面和剖面流网特征以及地下水渗透流速的空间变化规律．在此基础上，应用扩散边界层（ Ｄ Ｂ Ｌ） 理论模型分析了研究区不同部位的岩溶环境演化趋势．结果表明，由于库水位的大幅度抬升和防渗帷幕的实施，使得研究区防渗帷幕上游岩溶作用的强度减弱；而防渗帷幕下游岩溶作用的强度加强，并发生方解石的沉积作用．

The research into the groundwater seepage field and karst environment changes in a large water_filled impounding reservoir in the carbonate rock region is both an engineering problem and a theoretical problem of karst environment. The numerical simulation is adopted in this paper with the Gaobazhou and Geheyan reservoirs as examples to simulate the groundwater flow network features of the plane and profile of the groundwater seepage field and also to simulate the spatial change pattern in the groundwater seepage flow velocity before and after the water is filled in the impounding reservoir. On this basis, the theoretical model of the DBL (diffusion boundary layer) is applied to the analysis of the karst environment evolution trend at the different positions of the research region. The research results show that a large increase in the water level in the reservoir, and the construction of the seepage_proof curtain has resulted in the decrease in the karst intensity at the front of the curtain, but in the increase in the karst intensity at the back of the curtain where the calcite precipitation occurs. This phenomenon has been proved true in the water_filled Geheyan reservoir.