Experimental Study on the Penetration of Natural Unsaturated and Collapsible Loess Based on the Permeability Velocity

It is of great importance to study the behavior of loess moisture infiltration based on the loess permeability velocity to prevent geological disasters by loess collapsibility and get effective solutions for the problems of practical engineering. In this study, a custom-made permeation device was used to measure the permeation velocity of collapsible loess before and after water immersion and consolidation. The infiltration characteristics of the undisturbed collapsible loess under different consolidation pressures were discussed, and the influence of the pore characteristics on the permeability velocity was analyzed by the mercury injection test. Meanwhile, the correlations of various types of pores on the permeability velocity were studied by the gray relational entropy method to further reveal the water infiltration mechanism in loess. The results showed that the soil is compressed after consolidation and immersion tests, and the pore volume and pore diameter decreases. However, permeability velocity increases rather than decreases, and the self-weight collapsible state has the most significant permeability velocity. To the collapsible loess, the permeability velocity decreases with the increase of soil pore area. Additionally, small pores show the strongest correlation with permeability velocity. The conclusions of this study have a positive role in guiding foundation treatments and slope stability in collapsible loess areas.