LAUSR

Abstract In the Loess Plateau of China, loess has been remolded as the foundation of various construction projects with a long history. However, long-term seepage can change the saturated hydraulic conductivity of the remolded soil and hence affect the operation of loess construction engineering. Its formation mechanism is usually focused on the physical properties of soil, while neglecting the geochemical processes. In this study, the saturated permeability experiment performed on remolded loess is designed for better understanding of the change of saturated permeability and the underlying geochemical mechanism. Results show that the Ksat of remolded loess samples with various dry densities increases with time as a whole, while the change of Ksat with time can be divided into two stages: relatively stable type in the early stage and significant increasing type in the later stage. The saturated permeability is relatively stable due to the comprehensive effect of sedimentation of calcium cement, ion exchange and dissolution of clay minerals, while, the saturated permeability of remolded loess shows significantly enhanced behavior due to the major geochemical interaction of carbonate dissolution. In general, the leaching of carbonate in soil is the dominant factor for the change of saturated permeability of the remolded loess. Secondly, the cation exchange and clay minerals reactions determine the degree of particles aggregation and the development of pore space, which can also lead to increasing saturated permeability. The findings of the present study attempt to provide the theoretical basis for the protection of loess buildings and the prevention of the deterioration of loess construction structures in the Loess Plateau of China.