Study on Dynamic Elastic Modulus and Damping Ratio of Lime-Modified Expansive Soil

摘要

The rapid development of expressways cannot avoid objective problems such as subgrade settlement and pavement rutting during operation. Exploring the dynamic elastic characteristics of subgrade filling is the core of in-depth analysis of such problems, in which the dynamic elastic modulus and damping ratio are the most important parameters to exhibit the dynamic characteristics of the filling. Existing studies focus on the static indices of the filling, but rarely investigate the dynamic characteristics of the filling in combination with cyclic traffic loads, especially the dynamic characteristics of the expansive soil. To this end, relying on a highway lime-modified expansive soil subgrade engineering, this paper combined with indoor tests explored its dynamic modulus and damping ratio, and analyzed their influencing factors. The results showed that the dynamic elastic modulus decreased with the increase of the dynamic strain, and the damping ratio increased with the increase of the dynamic strain; the dynamic elastic modulus increased with the increase of the confining pressure, and the damping ratio decreased with the increase of the confining pressure. Moreover, at low strain (<0.002), the dynamic elastic modulus decreased by 70% with the dynamic strain, and the damping ratio increased by 75% with the dynamic strain. The research results provide a theoretical reference for exploring the dynamic parameters of lime-modified soil and further promoting its application in subgrade engineering.