Pore fluid salinity effects on physicochemical-compressive behaviour of reconstituted marine clays

Abstract It has been well recognized that pore fluid salinity significantly affects physical and mechanical properties of clays. However, how to correlate the pore fluid salinity effects on mechanical behaviour with physicochemical variations induced by pore fluid salinity changes is still pending. This study investigates the changes in liquid limit, oxide compositions and compressibility with pore fluid salinity, based on experimental data obtained from reconstituted specimens of two marine clays in China. It is found that oxide compositions vary little with the change in pore fluid salinity, indicating that no chemical reaction occurs during pore salt changing for the investigated clays. Such a finding means that the pore fluid salinity effects on compression behaviour of reconstituted clays can be attributed to the variations in physical properties. For the investigated marine clays with illite as predominant clay mineral, the void ratio at liquid limit is the crucial physical index of assessing the pore fluid salinity effects on the compression behaviour. The intrinsic compression concept is also introduced to compare the compression behaviour of reconstituted clays with and without pore salt. A quantitative approach is proposed to assess the pore fluid salinity effects on the compression behaviour of marine clays reconstituted at different initial water contents.