Dynamic Response of the Mechanically Stabilized Earth Walls with Different Reinforcement and Backfill Conditions

This paper presents the dynamic behavior of the mechanically stabilized earth (MSE) walls with different reinforcement and backfill conditions. Model shaking table tests were performed to determine the effect of density and wetness of the backfill on the dynamic response of the retaining structure. The tests were carried out for three different ground motions with increasing peak ground acceleration (PGA) values. Two different types of geosynthetics, namely, geotextiles and geogrids were used as reinforcements. Considering the effects of base excitations, acceleration responses at different locations of the structure, wall deformations, vertical settlements, and strain responses of the reinforcement were investigated. Acceleration was found to amplify with the height of the backfill. However, acceleration amplification was found to reduce by 18% for the geogrid reinforced wall compared to the unreinforced wall. It was observed from the test results that the overall performance of the structure deteriorated in the wet backfill condition. Wet backfill witnessed 30.8% more wall deformation in the unreinforced wall. However, maximum wall displacement was reduced by 28% for the geogrid reinforced wall as compared to the unreinforced wall in wet backfill. As compared to geogrids, higher deformation was observed in geotextile reinforcements. Strain in geogrid was found to be 32.4% less than the geotextile reinforced case for wet backfill conditions. Thus, it can be concluded that the geogrid reinforced wall displayed better performance as compared to other cases in both dry and wet backfill conditions.