摘要
为分析吹填珊瑚礁岛地下水的时空淡化规律,开展珊瑚礁岛地下水现场长期监测,获取了不同位置、不同深度地下水电导率的长期监测数据和定期取样测试核验数据;结合礁岛降雨监测资料,以电导率为地下水质评价的主要指标,分析地下水电导率在时间、空间尺度上的变化特征,探索礁岛地下水的淡化趋势及影响因素,通过随机森林模型进一步预测了钻孔内地下水电导率的变化规律。研究结果表明,珊瑚礁岛地下水电导率总体呈震荡下降趋势,地下水电导率与时间的关系可以用指数函数表示。地下水电导率随深度的增加而增大直至与海水的电导率相当后维持稳定,礁岛内相同深度地下水电导率呈现中间低、四周高的趋势。说明地下水的淡化从礁岛中心部位开始向四周延展,并发现在礁岛中部存在多个初始淡化中心点。地下水电导率受降雨入渗、潮汐作用、水文地质参数等多个因素的影响,随机森林模型预测5 a后潜水面下8 m处的电导率将逐渐稳定在10000μS/cm,地下水的淡化速率显著降低。
To analyze the spatiotemporal desalinization of groundwater in a reclaimed coral reef island,the long-term monitoring and regular sampling data of groundwater conductivity were collected from various locations and depths.The data were then analyzed in conjunction with rainfall monitoring data to examine the temporal and spatial changes in groundwater conductivity and explore the trend of groundwater desalination.The random forest model was used to predict the variation of groundwater conductivity in borehole.The findings indicate that the general trend of groundwater conductivity in the coral reef island is characterized by oscillation decline,with the relationship between groundwater conductivity and time following an exponential function.As depth increases,groundwater conductivity also increases until it reaches a level equivalent to seawater,after which it stabilizes.Moreover,the analysis reveals that at the same depth within the reef island,there is a pattern of low conductivity in the middle and higher conductivity around the periphery.This suggests that desalination starts from the central part of the island and progresses towards the periphery,with multiple initial desalination centers present in the central area.The groundwater conductivity is affected by many factors such as rainfall infiltration,tidal action and hydrogeological parameters.Based on the predictions made by the random forest model,it is anticipated that the conductivity at 8 m below the water surface will gradually stabilize at 10000μS/cm after 5 years,accompanied by a significant decrease in the desalination rate of groundwater.
作者
王雪晴
胡明鉴
彭赟
郑思维
WANG Xue-qing;HU Ming-jian;PENG Yun;ZHENG Si-wei(State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China;University of Chinese Academy of Sciences,Beijing 100049,China;College of Civil Engineering and Architecture,Guilin University of Technology,Guilin,Guangxi 541004,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2024年第1期257-266,共10页
Rock and Soil Mechanics
基金
国家重点研发计划课题(No.2022YFC3102101)
国家自然科学基金面上项目(No.42377176)。
关键词
吹填珊瑚礁岛
地下水
电导率
淡化规律
reclaimed coral reef island
groundwater
electrical conductivity
desalinization
