钙质珊瑚砂水理参数测定与涵淡水能力模拟

采用常规方法对我国南海某岛4个站位的钙质珊瑚砂样品进行实验室测定，并在此基础上利用模拟软件FEMWATER进行涵淡水能力的数值模拟。结果显示:南海表层钙质珊瑚砂以中细粒为主，其孔隙度在0.35~0.51之间，而渗透系数和给水度区域间差异较大，通常在0.023~12.73 m/d和0.01~0.10之间；岛礁淡水透镜体的厚度和资源储量与钙质珊瑚砂的水理参数间存在着密切联系，相比于其他参数，给水度对岛礁淡水透镜体的资源储量影响最大；与西沙群岛的钙质珊瑚砂相比，所测定的钙质珊瑚砂的粒度更细且颗粒多呈片状，磨圆度较差，反映了两者间的水动力条件和造礁生物方面的差异。

Measurement of hydrological parameters of coral sand and freshwater storage capacity simulation

In this study, calcareous coral sand samples from four stations on an island in the South China Sea were measured by common methods. Based on test parameters, numerical simulations of freshwater storage capacity were conducted by FEMWATER. The result indicates that the surface of the dredged calcareous coral sand in the South China Sea is mainly composed of medium and fine grains, and the porosity is mostly between 0. 35 and 0. 51. Meanwhile, the permeability coefficient and specific yield vary widely in different place, from 0. 023-12. 73 m/d and 0. 01-0. 10, respectively. There is a close relationship between the thickness and resource storage of fresh water lens and the hydrological parameters of calcareous coral sand. Among these parameters, the specific yield has the greatest influence on the resource storage of freshwater lens on the coral islands. Compared with the natural calcareous coral sand of Xisha Islands, the calcareous coral sand of this study is finer in size and particles are mostly flaky with poor roundness, which reflects the differences in hydrodynamic conditions and reef-building organisms.