裂隙-管道介质泉流域水文地质模拟试验

Hydrogeological Simulation Test of Fissure-Conduit Media in Springs Watershed

为了深入认识岩溶泉流域的流量过程影响因素和作用机制,以西南岩溶泉流域水文地质概念模型为原型,建立了实验室尺度下的裂隙-管道介质物理模型和数值模型。选取补给雨强、泉口直径、落水洞与开采井的位置作为影响因子,模拟了泉流量过程。试验结果表明：单次降水试验可以观测得到泉流量增加、平稳波动和衰减共三个阶段;同一泉口直径条件下,补给强度对泉流量衰减系数的影响极小,直径为3,4,5,7mm的泉口直径对应的衰减系数分别为0.003 6,0.006 7,0.011 5,0.012 9,泉口直径与衰减系数呈近似对数关系;落水洞汇流水量占泉流量的比例远大于裂隙;2~3 mm是微小裂隙与较大裂隙的过渡区域,两种类型的介质泉流量过程差异明显;开采井分别位于泉口附近、模型中间位置和落水洞时,泉流量衰减系数依次减小。

In order to deeply understand the factors and mechanism of the flow process in a karst spring basin,a fracture-conduit media physical model and a numerical model are established according to the hydrogeological conceptual model in a karst area of Southwest China.Recharge,spring vent,sinkhole,and pumping well are selected as the impacting factors to the simulate spring flow process.The results of the experiments show three phases of spring flow process under the single rainfall test：increase,stability,and attenuation.The results also show that recharge has a very small impact on the attenuation coefficient with the same spring vent diameter;the corresponding attenuation coefficients with 3,4,5,7 mm diameter are 0.003 6,0.006 7,0.011 5,0.012 9,a logarithmic relationship;the proportion of sinkhole flow is much larger than the fissure＇s.2-3mm is the transition zone of the larger fissure to the small cracks,the spring flows of the two types of media are quite different.The location of pumping wells is an important factor affecting the spring flow decay process,and the attenuation coefficients are decreased when the pumping well are located at near the spring vent,center of the model,and in the sinkhole.