Geotechnical properties of the South China Sea soft soil: a comparative study with the soils from Bohai Sea and Yellow Sea

This study illustrates and discusses the physical properties, mechanical behavior, and microscopic characteristics of the South China Sea soft soil, and a comparison with the Bohai Sea marine clay, the Yellow Sea soft clay, and some typical marine soils is presented. In addition, the mechanisms of the difference in the geotechnical properties of these marine soils are revealed. Compared with the soils from other sea areas, the South China Sea soft soil presents remarkable characteristics of higher water content, larger void ratio, higher liquid limit, and higher content of fine particles. Besides, the South China Sea soft soil shows higher compressibility. As shown in the microscopic characteristics, the South China Sea soft soil contains lower content of clay minerals; in addition, due to the depositional and geological environments with higher salinity and higher temperature, there are more macropores, connected pores, and trellis pores in the South China Sea soft soil, so it presents a more open, flocculated structure rather than a granular-connection structure like the Bohai Sea marine clay and the Yellow Sea soft clay. The results presented in this paper will provide an important theoretical basis for revealing the engineering properties of marine soils, and improve the insights for ensuring the safety of ocean engineering during construction and service periods.