Sensitivity Analysis of Parameters Affecting Bearing Capacity of Silt Soil Bridge Pile Foundation

Abstract

To study the bearing capacity of a silt soil bridge pile foundation in a river estuary, the pile foundation of the Nangang River Bridge in Hainan Province was chosen as the research object of this paper. ABAQUS finite-element software was used to establish the bridge pile–soil contact model, and the influence of foundation axial force, side friction resistance, and ultimate bearing capacity under the different pile lengths and pile diameters were analyzed. At the same time, the influence of the silt soil layer on the bearing capacity of the bridge in the silt soil layer was analyzed. The calculation results showed that when the pile diameter was fixed and the pile length increased from 30 m to 60 m, the bearing capacity of the pile foundation increased by 10,200 kN, while when the pile length increased to 60 m, the bearing capacity only increased by 3,400 kN. When the pile diameter increased from 0.6 m to 1.5 m, the bearing capacity of the pile foundation increased by 10,200 kN, but when the pile diameter exceeds 1.5 m, the bearing capacity only increased by 3,400 kN. When the ratio of the pile diameter to the pile length was 1∶40, the pile diameter and pile length can give full play to the maximum bearing capacity. When the depth of the silt soil increases, the bearing capacity of the pile foundation gradually decreased. The reason was that the side friction of silt is very small compared with other soils, which leads to the smaller bearing capacity. The bearing capacity of pile foundations can be improved by enlarging the pile diameter, increasing the pile length, increasing the cohesive force of the soil around the pile, and changing the position of the load box. This study provides a reference for the design and construction of bridge pile foundations in silt-filled soil in a river estuary.