Engineering behavior and constitutive model of artificial soft clay considering pore water salinity effect

The soft marine clay, which is deposited under the marine environment in the north plain of Jiangsu Province, is rich of montmorillonite mineral and saline pore water. During the post-sedimentary period, the soil suffers the invasion of the surface and underground freshwater, leading to the alteration and reduction of pore water salinity. Presently, the safety evaluation is generally based on the in-situ soil strength in the current environment. Hence, this non-consideration of the pore water salinity alteration may result in insufficient redundancy and potential risk. To clarify the evolution of the hydro-mechanical behavior of soils due to the alteration of pore water salinity during the operation of the coastal infrastructure, the impact of pore water salinity and clay mineral on the soil behavior is necessary to be investigated. To simplify the mineralogical influence, commercial kaolin and bentonite are selected. The physical and mechanical properties of artificial clay changing with pore water salinities (NaCl solution) are investigated using the Atterberg limits tests, oedometer tests and tri-axial tests. The results show that the liquid limits, compression index C_c and swelling index C_s of the artificial clay containing bentonite decrease with the pore water salinity, and its internal friction angle increases with the pore water salinity. Meanwhile, the liquid limits, compression index C_c, swelling index C_s and consolidated undrained strength of Kaolin are not affected by the pore water salinity. Finally, based on the test results, modified Cambridge model and BBM model, an updated constitutive model considering pore water salinity effect represented by the osmotic suction is proposed, and the