Consolidation behaviors of soft marine clay in Lianyungang under desalination environment of pore water

The marine soft clays, the quaternary sediments, are widely deposited in the sea transgression/regression environment in Lianyungang, Jiangsu Province, whose behaviors are focused recently with the implementation of the coastal development strategy. The salinity of pore water during deposition is relatively high, and with the erosion of the surface or underground freshwater, the desalination of pore water occurs, whilst its effect on soil behaviors of the natural soft clays is still unclear. The piezo-cone penetration tests (CPTu) and physical property experiments of the soft clays with salinity of pore water of 0.1% and 4.9% at two sites, e.g. Lianyungang-Linyi highway and Linhai highway, are conducted. The higher strength of the soils with more salinity at the same depth is observed, but they have the similar deposition environment, ratios of water content to liquid limit, particle-size distributions and mineral compositions. To further clarify the effect of pore water, the paralleled percolation and oedometer tests with the synthetic solution and deionized water are performed. The results show that the parameters of oedometer modulus E_Oed, consolidation coefficient C_v and hydraulic conductivity k with the synthetic solution are higher than those with deionized water, while the compression index C_c, swelling index C_s and secondary consolidation coefficient C_α are on the contrary. Those results will deepen the understanding of behaviors of Lianyungang marine clays and provide the reference for the offshore engineering.