Dynamic Characteristics of Reconstituted Silt Influenced by Axial Unloading Intensity and Fine Particle Content

Abstract

The stress disturbance induced by adjacent construction has a significant impact on the dynamic characteristics of the soil, resulting in complex long-term tunnel settlement under train vibration load. Through a series of dynamic triaxial tests, the effects of different fine particle contents and axial unloading intensities on the permanent axial deformation and excess pore water pressure of reconstituted silt under long-term cyclic loading were investigated. The findings show that as fine particle content in the silt increases, the threshold dynamic stress and failure cycle number decrease at first, then increase, reaching a minimum value at 10% fine particle content. The dynamic characteristics of silt are significantly affected by axial unloading, and the dynamic stress threshold amplitude of a soil sample decreases as the unloading strength increases. The accumulation of silt deformation caused by long-term cyclic load can be effectively controlled by ensuring drainage conditions.