公路建设对湿地水系连通性的阻隔效应研究

发布时间：2018-02-24 02:52

本文关键词： 环境工程阻隔效应 Visual Modflow 水系连通湿地公路建设　出处：《公路交通科技》2017年11期 　论文类型：期刊论文

【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。
[Abstract]:Taking the peat marsh wetland of Bajiazi section of Huibian Expressway in Yanbian area as the target research area, the stratigraphic distribution of the section is proved by field exploration test, and the field pumping test and tracer test are carried out. The relevant hydrogeological parameters are determined. Based on the hydrogeological characteristics of the study area, the vertical direction of the simulated area is generalized into three layers by using Visual Modflow, and the parameters are identified by the model according to the calculated results of the pumping test. Finally, the average conductivity of the model area is 141m2 / d, the average water release coefficient is 2.61 脳 10 ~ (-4), the water supply degree is 0.3, and the porosity is 0.6. The groundwater flow model and the groundwater solute transport model based on numerical simulation are established. This paper analyzes the barrier effect of highway construction on the connectivity of wetland water system, and compares the changes of groundwater level, groundwater flow field and groundwater flow in highway coverage area with or without highway. Under the condition of highway, the water head on the north side of the highway is generally higher than that on the south side, and the groundwater level difference between the two sides of the roadbed increases by about 0.5 m compared with that when there is no highway. It can be seen that the construction of the highway has a certain influence on the groundwater flow. The discharge of highway overlay area is reduced by about 60%, especially that of the south side of highway coverage area is decreased by about 70% compared with that without highway. At the same time, the solute migration of groundwater is simulated with nitrogen element as the object. The influence of highway construction on wetland solute migration is predicted. The results show that the concentration distribution on both sides of the highway is different, and the concentration of solute in the upstream part of the highway is larger than that in the case of no highway. It can be seen that highway construction has an obvious barrier effect on solute migration in wet areas.
【作者单位】：广西师范大学环境与资源学院;北京师范大学水科学研究院;
【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)
【分类号】：TV213.4;U412.2

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