Study on the Critical Height of Secondary Salinization of Silty Soil Subgrade in the Yellow River Impact Plain Area

To study the critical height of secondary salinization of silty soil subgrade, this paper examines the salt migration law in the secondary salinization of the non-saline soil subgrade in the Yellow River impact plain area via laboratory and numerical analyses using COMSOL Multiphysics. The results show that (1) if the top of subgrade has not yet formed poly salt, then the internal roadbed will also not form poly salt. and it shows the trend of gradually decreasing from the bottom to the salt distribution in the subgrade; (2) the relationship among the weak internal saline soil formation of critical height, the groundwater mineralization degree, and the underground water level at the top of the subgrade can be used to establish an approximate correlation and regression formula for the Yellow River impact plain area for estimating the weak internal saline soil formation of critical height; and (3) the influence of the groundwater mineralization degree on the secondary salinization of silty soil subgrade in the Yellow River impact plain area is significantly higher than those of the buried depth of groundwater and the filling height of subgrade.