公路建设对湿地水系连通性的阻隔效应研究  

Study on Separation Effect of Highway Construction on Wetland Hydrologic Connectivity

作　　者：李艺[1] 王红旗[2] 李晓珂[2] 

机构地区：[1]广西师范大学环境与资源学院,广西桂林541004 [2]北京师范大学水科学研究院,北京100875

出　　处：《公路交通科技》2017年第11期143-150,158,共9页Journal of Highway and Transportation Research and Development

基　　金：交通运输部西部交通科技建设项目(20113186701290);广西师范大学重点项目(2014ZD007)

摘　　要：以延边地区珲乌高速公路八家子路段草炭土沼泽湿地作为目标研究区,通过现场勘探试验,探明了该路段的地层分布情况,通过现场抽水试验和示踪试验,确定了相关的水文地质参数。并在此基础上,根据研究区水文地质特征,利用Visual Modflow将模拟区垂向概化为3层;根据抽水试验计算结果,并通过模型识别调参,最后确定模型区的平均导水系数为141 m2/d,平均释水系数为2.61×10-4,给水度为0.3,孔隙度为0.6。建立了基于数值模拟的地下水水流模型和地下水溶质迁移模型,分析了公路建设对湿地水系连通性所产生的阻隔效应;并对有无公路情况下地下水水位、地下水流场变化及公路覆盖区地下水流量的变化进行对比。研究结果表明,在有公路情况下,导致公路北侧水头普遍高于南侧,路基两侧地下水水位差较无公路时增加了0.5 m左右,可见公路建设对地下水流产生了一定的影响;另外,公路覆盖区流量较无公路时减小了60%左右,尤其是公路覆盖区南侧的流量较无公路时减少了70%左右。同时,以氮元素为对象进行地下水溶质迁移模拟,预测公路建设对湿地溶质迁移所产生的影响,研究结果表明,在有公路情况下,公路两侧的浓度分布出现了浓度差,公路上游部分区域溶质浓度较无公路情况下较大,可见公路建设对湿地区溶质迁移产生了明显的阻隔效应。Choosing the turfy marshland in Bajiazi road section of Hunchun--Ulanhot expressway in Yanbian area as the research objective area, the stratigraphic distribution is explored by field test, and the correlated hydrogeology parameters are determined by field pumping test and tracer test. The simulation area is vertically generalized to 3 levels based on the Visual Modflow, and the average transmissibility coefficient, average water release coefficient, specific yield and porosity are determined as 141 m2/d, 2.61 x 10-4, 0. 3 and 0.6 respectively by the calculation result of field pumping rest and model parameter identification and adjustment. On this basis, the groundwater flowing model and groundwater solute migration model based on numerical simulation are established using Visual Modflow. The separation effect of the highway construction on the wetland hydrologic connectivity is analyzed. Meanwhile, the variation of groundwater level, groundwater flow field with and without highway circumstances and the variation of groundwater flow in highway coverage area are compared. The result indicates that （ 1 ） the existence of highway leads to the water head on the north side of the highway is generally higher than the south side, the groundwater level difference at both sides of highway subgrade is 0.5 m higher than that without highway, and the groundwater flow going through highway area is decreased obviously by around 60% than that without highway, especially the water flow is decreased by around 70% in the southern area of the highway covering area. Additionally, groundwater solute transfer is simulated based on the transferring of nitrogen element to predict the effect of highway construction on solute transport in wetland. The result shows the solute concentration gradient exists at both sides of highway, particularly in the part of highway upstream area, which indicates the obviously separation effect of highway construction on the wetland solute transport.

关 键 词：环境工程 阻隔效应 VISUAL MODFLOW 水系连通 湿地 公路建设 

分 类 号：X143[环境科学与工程—环境科学]