The influence of pore fluid composition on the residual shear strength of some natural clayey soils

This paper analyses the influence of pore fluid composition on the residual shear strength of three Italian clayey soils characterized by different values of clay fraction and of liquid limit. The experiments were performed on specimens reconstituted with water, by exposing them alternately to a saturated NaCl solution and to water in the course of direct shear tests. The results show that ion diffusion inward or outward of the pore fluid produces large changes in the residual shear strength. The largest changes are produced in the soils with high activity. However, noticeable changes are also exhibited by a less active soil