Experimental Study on Collapsibility of Coarse-Grained Saline Soil Subgrade in the Qarhan Salt Lake Area, Western China

The collapsibility of chlorine saline soil that widely distributed in the Qarhan Salt Lake area is of significant concern for highway construction in the Qaidam Basin, western China. To investigate the collapse behavior of coarse-grained saline soil subgrade, a study was conducted by a combination of in situ monitoring and laboratory tests based on Sebei-Qarhan Highway. The results show that the collapsibility of coarse-grained saline soil is closely related to the particle composition. The saline soil with a high content of coarse particles shows an obvious skeleton function in soil structure after wetting, the collapse coefficient increases at first and then decreased with the increase of fine particles, having a critical value. The increasing salt content caused an increase in the critical value, and the collapsibility of the coarse-grained saline soil is not sensitive to the variation of the salt content when it is at a low level.