Analysis of the Influence Factors of a Hydraulic Compactor to Reinforce the Subgrade on the Back of an Abutment

Abstract

To study the dynamic influence of a hydraulic compactor reinforcing the subgrade on the back of an abutment and based on the subgrade filling project of an abutment back in the transition section of a high-speed bridge and tunnel, the interaction model of rammer, subgrade, and abutment is established using ABAQUS. The accuracy of the model is verified using full-scale ramming tests. In the process of simulation, the maximum dynamic displacement and maximum dynamic strain of the abutment are taken as evaluation indexes. The influence of factors such as the dropping distance, the distance between tamping point and the abutment, the initial compactness of the subgrade, the strength grade of the abutment concrete, and the top support conditions of the abutment on the abutment deformation were analyzed. The results show that: (1) the error between the measured value and the simulated value is less than 10%, the variation trend of the abutment dynamic displacement and the dynamic strain along the abutment height is in line with the convention, and the simulation model is reliable. (2) The maximum dynamic displacement and strain of the abutment increase linearly with the increase of the dropping distance and increase exponentially with the decrease of distance between the tamping point and the abutment. (3) When the initial compactness of the subgrade increases from 75% to 95%, the maximum dynamic displacement and the maximum dynamic strain of the abutment are basically the same, and the initial compactness of subgrade has little effect on the deformation of the abutment. (4) The improvement of the concrete strength grade of the abutment has a significant effect on the reduction of the abutment deformation. (5) When there is no expansion joint at the top of the abutment, the maximum dynamic displacement and the maximum dynamic strain are reduced by 75% and 24% compared with those with an expansion joint. In the process of reinforcement, the method of temporarily blocking of bridge expansion joint can be used to change the stress form of the abutment.