Effects of Fine‐Grained Particles and Sodium Chloride Solution on Physical Properties and Residual Strength of Granite Residual Soils: An Experimental Study

Stability analyses of earth structures composed of granite residual soils (GRSs) are consistently essential, particularly under significant vibrational loading. In these analyses, it is stressed that the residual strength ought to be applied instead of peak strength. Consequently, the residual strength of such soils should be precisely assessed to minimize damage. Moreover, salt salinization is a prevalent problem, especially in coastal regions. A laboratory study was performed to explore the sodium chloride (NaCl) effect on the residual strength of GRSs. Two kinds of GRS samples with disparate ratios of fine‐grained particles (FGPs) were treated with four NaCl concentrations. The physical property and ring shear tests were then carried out. The findings showed that as the FGPs rose, the residual strength declined, and the values of postpeak attenuation were prone to grow under salt solution conditions. When the salt content increased under an identical normal stress, the peak and residual strength of GRSs initially dropped and then rose, respectively. Meanwhile, the residual friction angle and residual cohesion initially decreased and then increased. Finally, based on linear regression, a statistically significant correlation between the residual frictional angle and limit moisture content indicators under NaCl solution was observed for GRSs.