The structural evolution of remolded loess due to water infiltration

In order to study the process of structural changes in remolded loess caused by water infiltration, the structural change characteristics and effects of the remolded loess before and after water infiltration are studied using mechanical, CT and simulation tests. The results show that: (1) The peak frequency of the equivalent diameter of the remolded loess particles after infiltration is between 10μm~30μm, and the sphericity value of remolded loess particles after infiltration becomes significantly smaller, which is concentrated in the interval greater than 0.8 before infiltration and extends to the interval range of 0.6-1. (2) After saturation and infiltration, the total porosity and pore connectivity of the remolded loess increased significantly, and the three-dimensional total porosity of the loess increased by 27.51% after infiltration, and the water infiltration only caused the obvious expansion of the macropores, and the rapid development of the macropores led to the increase of the pore area ratio to 17.9%. It shows that macropores are the main reason for the development of pore structure and the deterioration of soil structure. (3) After the infiltration test, the porosity of the remolded loess with a specific surface area of less than 0.15 increased to 71.23%, indicating that the sample developed from a compact state to a loose and softened state. The decrease of the pore-throat ratio and the increase of the coordination number of the remolded loess after infiltration indicate that the water forms a large-scale channel with good fluidity in the sample, and the scale of the complex pore structure in the soil decreases, thereby increasing the dominant seepage channel of the loess. (4) The migration of fine particles and structural damage caused by water entering the loess are the reasons for its collapsibility, and at the same time, the strength of the reshaped loess will be reduced after water infiltration. The results of this study provide a reference for revealing the damage mechanism and process of water.