Abstract: In soft ground, the lateral displacement of piled foundation and the additional bending moment of the bridge pile caused by the surcharge load is an extremely negative impact on the safety of the bridge. Through the introduction of specific project, the influences of the unilateral and bilateral surcharge load on the lateral displacement and the internal force of the bridge piled foundation are analyzed in-depth using the finite element analysis; and the calculation results and the measured results are compared. According to above analyses, the change rules of the lateral displacement and the internal force of the bridge piled foundation are further understood. By the impact of unilateral surcharge, the lateral offset and bending moment on the pile is much more significant. The inflection point of the pile is occurred at the interface between the soft soil and hard soil. While the additional bending moment of the pile is significant, it will result in pile cracking. By the impact of bilateral surcharge, the lateral offset of the piled foundation is determined by both sides of the load. Unloading both sides at the same time is less impact on the lateral offset of the piled foundation; but it plays an important role in reducing additional moment of the pile.

Key words: soft ground, surcharge load, piled foundation, lateral displacement, finite element analysis