Abstract:Nowadays, the microscopic analysis of the evolution process mechanism of loess liquefaction is a hot topic. In this study, we attempt to investigate the nature and influence factors of loess liquefaction through dynamic tests. We use the CT scanning test to study the macroscopic change of loess liquefaction. The results show that the primary cause of liquid level rise is the water absorption of alkalescent salt cement. When specimens become highly saturated, the cementing material between the particles surrounding the soil macropores is destroyed. Then, the effective stress is zero and the soil is liquefied. The difference in the microstructure of soil can also influence the increase in liquid level and the failure strength of soil. Liquefaction tests on three kinds of loess (low-cohesive silt, silty sand, and silty clay) indicate that the dynamic loading time of the low-cohesive silt is the shortest. In other words, the liquefaction of low-cohesive silt is most severe and the silty sand is in medium liquefaction; by comparison, the silty clay is difficult to liquefy. The analysis of soil microstructure parameters with scanning electron microscope indicated that the chemical element (Ca/Fe) ratios of the cements around the soil particles, and the particle size distribution and pore size of the soil particles affect the degree of liquefaction.
