人工沙滩对海水入侵影响评价的数值模拟研究

以广东省珠海市2018年完工的唐家湾沙滩为研究对象,基于OpenGeoSys程序构建海水入侵数值模型,根据水文地质调查数据,建立沙滩修复前地下水运动的数学模型,利用地下水盐度历史数据进行参数率定与模型验证。在该模型基础上,根据填沙的水文地质参数,改变模型相应部分的属性,分析针对不同人工沙滩修复方案情景下的咸淡水界面运移规律。结果表明：人工填沙可加速海水入侵,填沙厚度对海水入侵程度影响较小;增加填沙宽度可以有效缓解海水入侵,当填沙宽度达到50 m时,可驱退咸淡水界面至沙滩修复前的状态。

Numerical Simulation of Impact Evaluation of Beach Nourishment on Seawater Intrusion

Taking Tangjiawan Beach built in 2018 in Zhuhai, Guangdong as the research object, a numerical model of seawater intrusion was constructed based on OpenGeoSys program. According to hydrogeological survey data, a mathematical model of groundwater movement was established before the restoration of the beach, and historical data of groundwater salinity was used for parameter calibration and model validation. On the basis of this model, according to the hydrogeological parameters of sand filling, the movement rules of the interface between saltwater and freshwater under different beach nourishment restoration plans were analyzed by changing the attributes of the corresponding part of the model. The results showed that beach nourishment would accelerate seawater intrusion, but the thickness of sand filling had little impact on seawater intrusion. Increasing the width of sand filling could effectively alleviate seawater intrusion. When the width of sand filling reached 50 meters, the interface between saltwater and freshwater could return to the state before the beach was restored.