Centrifugal Model Test and Simulation of Geogrid Reinforced Backfill and EPS Interlayer on Bridge Abutment

In this paper, the use of geotechnical centrifuge and numerical modeling techniques to investigate the influence of geogrid reinforcement and EPS interlayer on the lateral earth pressure and the backfill surface settlements behind gravity abutment and pile-supported abutment is reported. According to the principle of equal strain, the abutment back structure, foundation, backfill material, grid and interlayer material were simulated, and the centrifugal model test for two types of abutments was carried out with a model scale of n = 62.5, 40, respectively. The tests showed that the reinforcement of the geogrid could reduce the surface settlement of backfill and the lateral earth pressure of the backfill on the back of abutment. After setting the EPS interlayer, the influence of abutment displacement on earth pressure could be eliminated, and the earth pressure of the backfill material on the abutment back was significantly reduced. The “interlayer + geogrid” structure further reduced the earth pressure of backfill material on the abutment back. The existence of the EPS interlayer adjusted the strain distribution of the reinforced material, significantly increasing the strain of the reinforced material near the abutment, which was conducive to the reinforcement effect. The above research conclusions could provide a basis for the design and practical application of abutment backfill materials