Low embankment dynamic response under vehicle traffic loads in arid-oasis areas

Abstract

The use of low embankments is of significant concern for ecological protection in arid-oasis areas. Based on the project of Sansha Expressway located in Kashgar City, Xinjiang, China, physical model tests were conducted in this study to investigate the dynamic response of the low embankment as per the effects of road structure, load amplitude, load frequency, load cycle, and moisture content. The dynamic stress is shown to increase with load amplitude while the dynamic elastic modulus decreases with load amplitude under short-term loading. The load frequency slightly influences the soil’s dynamic behavior; higher frequencies can improve the dynamic elastic modulus of the subgrade soil. The moisture content has greater influence on the mechanical properties of the subsoil than that of subgrade layer. The subgrade bears the majority of the traffic load as the stress dissipates to 37% of the whole value on its surface. The number of load cycles has the greatest effect on the dynamic response among the influencing factors tested. The dynamic elastic modulus with the type of long-term dynamic loading is only 40%–52% of that with static loading across the entire depth range. The dynamic stress shows significant accumulation with load cycles over the long-term dynamic loading test and becomes stable after 8 × 104 cycles of loading. An equation is established to quantify the cumulative dynamic stress in the low embankment under long-term dynamic loading conditions.