Rock and Soil Mechanics ›› 2022, Vol. 43 ›› Issue (5): 1226-1236.doi: 10.16285/j.rsm.2021.5145

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Formation process of underground freshwater based on zoning and stratification of coral reef island

JU Yuan-jiang1, 2, HU Ming-jian1, LIU Yang2, ZHU Xu2, QIN Kun-kun2   

  1. 1. State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, Hubei 430071, China 2. School of Resources and Geosciences, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China
  • Online:2022-05-13 Published:2022-07-04
  • Contact: HU Ming-jian, male, born in 1974, PhD, Research fellow mainly engaged in research on marine geotechnical engineering and landslide and debris flow disasters. E-mail: E-mail:
  • About author: JU Yuan-jiang, male, born in 1975, PhD, Associate Professor, mainly engaged in research on landslide debris flow and groundwater dynamics.
  • Supported by:
    the National Natural Science Foundation of China (41572304, 41877271) and the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA13010301).


In order to understand the significance of stratum stratification characteristics during the formation of underground freshwater lens in the coral reef islands, the particle size distribution (PSD) of the samples drilled at various depths of a coral reef island in the South China Sea is analyzed. The zone and strata of the island are determined according to the PSD characteristics in the horizontal and vertical directions, respectively. The area of each zone is determined based on the range covered by each drilling, and the thickness of each stratum is determined by the thickness of the samples with similar particle size in each drill hole. The permeability of the strata is controlled by the PSD of different zones and strata of the loose layer above the reef limestone, while the vertical and horizontal permeabilities control the difficulty of formation of the underground freshwater lens, the total thickness of the freshwater lens, and the thickness of the transition zone. The numerical model is established by considering the total area of the island and the number of strata. Finally, the numerical results of chloride ion concentration characteristics in the groundwater at different times, horizontal positions and depths are obtained.

Key words: coral reef island, seawater desalination, zoning and stratification of island