关键词: 桥梁, 安全性, 有限元, 非对称堆载, 变形

Abstract: Aiming at the usually reported accidents induced by soil massively stacked in the bridge side，a numerical simulation for the behavior of pile foundation of a highway ramp bridge subjected to surcharge load was carried out． A computational model of bridge，foundation soil，stacked soil was constructed through the finite element software ABAQUS，and variables such as varied structural forms of bridges and pile dimensions were selected． The effects of soil squeezing，deformation of foundation soil，pile-soil coupling relationship，overall displacement and internal force of the bridge were modeled to assess the safety status of the bridge． The influence of dimensions of the pile on the stability of bridge structure was discussed according to the deformation law of the foundation soil，and the safety status of different bridge structures under asymmetric loading were comparatively analyzed． The results show: when mass earth is heaped laterally on the bridge，the bending moment and axial force of the bridge increase by 177. 7% and 27. 3% ，respectively; the internal forces of the main pier and upper structure has no obvious change，indicating that the ramp bridge is safe; the deformation，moment change and the lateral displacement of the bridge pile foundation are consistent with the existing conclusions; the lateral displacement mainly occurs in the layer of soft soil，which may exceed the allowable value under large loading; decreasing the height of the stacked soil and increasing the space between soil piles can prevent the deformation of the foundation soil and reduce the displacements of the bridge structure; the width of the stacked soil has significant influence on the lateral displacements of the foundation soil and little influence on the sink of the foundation soil; clearing the soil near the bridge can effectively control pile foundation deformation and horizontal displacement; the bridge is prone to greater structural deformation under the influence of massively stacked soil after setting expansion joints and supports; linear curvature and load position also have an effect on expansion joint of bridge deformation．

Key words: bridge, safety, finite element, asymmetric surcharge, deformation