Experimental investigation on the accumulated strain of coarse-grained soil reinforced by geogrid under high-cycle cyclic loading

In this study, a series of cyclic triaxial tests were conducted to study the accumulated strain of coarse-grained soil reinforced with geogrids, and the effect of the number of geogrid layers, confining pressure and cyclic stress amplitude was investigated in detail. The test results show that the final accumulated axial strain of the soils reinforced with geogrids is less than that without reinforcement, and less accumulated axial strain is generated for the specimens with more geogrid layers under identical cyclic loading. The results also show that a higher confining pressure or a lower cyclic stress amplitude yields less accumulated axial strain for the reinforced soils. Furthermore, the plastic shakedown limits are determined by the criterion proposed by Chen et al. It indicates that the plastic shakedown limit increases significantly when one layer of geogrid is incorporated into the specimen and then tends to level off with a continuous increase in the number of geogrid layers. Moreover, a higher confining pressure yields a higher plastic shakedown limit for the soils reinforced with geogrid. The results demonstrated that the use of geogrid can be an effective method to reduce the accumulated deformation of subgrade filling materials under high-cycle traffic loading.