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在河流入海地段，由于海水沿河上溯和河流水动力强度变弱，河水所携带的细粒悬浮物在河床表面形成一层低渗透性覆盖层，从而限制河流与地下水之间的水盐交互作用，深入研究低渗透淤泥层影响下感潮河流与地下水的水盐交换对于滨海地下水资源利用与保护具有重要的科学意义与应用价值。本文以山东半岛大沽河河口区为研究区，在现场水文地质调查和监测的基础上，建立了场地尺度的地下水数值模型，首次研究了河床表面低渗透淤泥层影响下地下水-盐动力学特征和感潮河流-地下水水盐交换通量，定量分析了低渗透层的渗透性与厚度变化对感潮河流-地下水交换过程的影响效应。研究表明，在不同的低渗透层条件下，初始阶段时咸水楔的长度增加，咸水楔回退率有所减小，大约100 d后逐渐达到最小值，之后咸水楔的长度突然减小，咸水楔回退率快速增加，大约600 d后逐渐趋于稳定。另外，河流-地下水水盐的交换通量呈周期性变化，随着低渗透层的渗透性降低或厚度增加，河流-地下水水交换通量和盐交换通量的变化量减小。
Abstract：In the area where the river enters the sea, due to the weak hydrodynamic strength of the river and the water upstream, the fine suspended matter carried by the river forms a low permeability covering layer on the river bed surface, thus limiting the water-salt interaction between the river and groundwater. The in-depth study on the exchange of water and salt between tidal river flow and groundwater under the influence of low permeability silt layer has important scientific significance and application value for the utilization and protection of coastal groundwater resources. Taking the Dagu River estuary area of Shandong Peninsula as the study area, a site-scale groundwater numerical model is established on the basis of on-site hydrogeological investigation and monitoring. The groundwater salt dynamics characteristics and the fluxes of tidal river-groundwater water and salt exchange under the influence of low permeability silt layer on the river bed surface are studied for the first time. The effect of permeability and thickness change of low permeability layer on tidal river-groundwater exchange process is quantitatively analyzed. The research shows that under different conditions of low permeability layer, the length of the saline wedge increases and the regression rate of the saline wedge decreases at the initial stage, and gradually reaches the minimum value after about 100 days, then the length of the saline wedge suddenly decreases and the regression rate of the saline wedge increases rapidly, and the regression rate gradually becomes stable after about 600 days. In addition, the fluxes of river-groundwater water and salt exchange show periodic changes, and the fluxes of river-groundwater water and salt exchange decrease with the decrease of permeability or the increase of thickness of the low permeability layer.
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基本信息:
DOI：10.16441/j.cnki.hdxb.20250043
中图分类号:P333;P641.2
引用信息:
[1]吴越,郑天元,张博,等.河床低渗透层影响下感潮河流-地下水交换研究[J].中国海洋大学学报(自然科学版),2025,55(12):115-125.DOI:10.16441/j.cnki.hdxb.20250043.
基金信息:
国家自然科学基金项目(42202270,42422207)资助~~