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

To study the bearing capacity of the silt soil bridge pile foundation in the river estuary, the pile foundation of the Nangang River Bridge in Hainan Province was choosen as the research object in this paper. Through ABAQUS finite element software established the bridge pile-soil contact model, and analyzed the influence of foundation axial force, side friction resistance and ultimate bearing capacity under the different pile lengths and pile diameters. At the same time, the influence in the silt soil layer on the bearing capacity of 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 10200 kN, while when the pile length increased to 60 m, the bearing capacity only increased by 3400 kN. When the pile diameter increased from 0.6 m to 1.5 m, the bearing capacity of the pile foundation increased by 10200 kN, but when the pile diameter exceeds 1.5 m, the bearing capacity only increased by 3400 kN. When the ratio of pile diameter to pile length was 1/40, the pile diameter and pile length can give full play to the maximum bearing capacity. With the depth of the silt soil increasing, 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 foundation 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 the river estuary.