摘要
钙质砂的水理性质对岛礁地下淡水透镜体的形成至关重要。通过室内试验的方法从透水性、容水性和给水性3个方面对南海钙质砂的水理性质进行了研究,并在此基础上进一步结合数值模拟手段,探讨了上述相关性质对岛礁淡水透镜体形成的影响。结果表明:南海钙质砂多具有级配不良且不均匀的特征;其渗透系数通常在0.023~110m/d之间,区域间差异较大,而孔隙度和给水度则主要集中在0.40~0.55和0.012~0.310之间,与同粒径范围的陆源砂相比,呈现出容水性好但给水性偏低的特征。钙质砂的水理性质对岛礁地下淡水透镜体形成的影响主要体现在流速、厚度、资源储量以及形成时间等方面,其中钙质砂的透水性越好,地下水中的流速越快,咸淡水间的混合作用越强,导致淡水透镜体的厚度越薄,储量越少;给水性则主要影响钙质砂中淡水透镜体的资源储量,对淡水透镜体的厚度及形状影响较小。
The hydrological properties of calcareous sand in South China Sea are very important for the study of the formation of underground freshwater lens on islands.The permeability,specific water capacity,and specific yield of calcareous sands were studied by laboratory test first;and combined with the two-dimensional numerical model,their influence on the formation of freshwater lens of islands was analyzed.The result shows that the calcareous sand in South China Sea is poorly gradated and unevenly distributed,and the permeability coefficient is usually between 0.023and 110m/d,greatly changed in the study area.The porosity and specific yield are mainly between 0.40-0.55and 0.012-0.310,respectively,which reflects that the calcareous sand has the characteristics of good water capacity but poor water supply compared with the continental sand with the same particle size range.The influence of hydrological properties of calcareous sand on the formation of freshwater lens is mainly reflected in the velocity,thickness,resource reserve,and formation time.Among them,the better the permeability of calcareous sand is,the faster the groundwater flow rate is,which strengthens the mixing effect between brackish and fresh water,resulting in a thinner freshwater lens and less reserves.Specific yield mainly affects the resources and reserves of freshwater lens in calcareous sand,but has little influence on the thickness and shape of freshwater lens.
作者
盛冲
许鹤华
张云帆
张文涛
任自强
Sheng Chong;Xu Hehua;Zhang Yunfan;Zhang Wentao;Ren Ziqiang(Key Laboratory of Ocean and Marginal Sea Geology(South China Sea Institute of Oceanology),Chinese Academy of Sciences,Guangzhou 510301,China;University of Chinese Academy of Sciences,Beijing100049,China;Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou),Guangzhou 511458,China;Innovation Academy of South China Sea Ecology and Environmental Engineering,Chinese Academy of Sciences,Guangzhou 510301,China)
出处
《吉林大学学报（地球科学版）》
EI
CAS
CSCD
北大核心
2020年第4期1127-1138,共12页
Journal of Jilin University：Earth Science Edition
基金
国家自然科学基金项目(91428205,41376061)
中国科学院战略性先导科技专项(A类)(XDA13010303)
南方海洋科学与工程广东省实验室(广州)人才团队引进重大专项(GML2019ZD0104)。
关键词
南海
钙质砂
水理性质
淡水透镜体
数值模拟
South China Sea
calcareous sands
hydrological properties
freshwater lens
numerical simulation
