The influence of salt contents on the compressibility of remolded loess soils

Salts have been widely reported to exist in loess and play an important role in the soil mechanical behavior. In recent years, as several land creation megaprojects have been undertaken on the Chinese Loess Plateau, the salt migration paths have been influenced by large-scale loess fill, and land subsidence has become a major new geohazard in the loess fill area. Thus, it is crucial to elucidate the compressibility of remolded loess under various salt concentrations. In the present work, Lanzhou and Xi’an loess samples were selected, and the original soils and some artificially graded soils were prepared for odometer tests after various treatments with soluble or insoluble salts. The results revealed a positive but limited effect of soluble salts in reducing the compressibility of loess, while the compressibility could be significantly reduced by adding an insoluble salt. Furthermore, the effect of the insoluble salt was related to the soil grading features. The soil structure could be strengthened more effectively when it was well graded and possessed a high clay content. The obtained results demonstrate that introducing appropriate amounts of insoluble salt and clay particles into remolded loess represents an effective approach for reducing the risk of land subsidence.