Numerical simulation study on erosion of dual pile foundation of mountainous road bridge

Abstract

Aimed to investigate the erosion distribution characteristics of dual pile foundations of mountainous road bridges under sand laden flow, a three-dimensional erosion numerical model of the dual pile foundation was established using Fluent. The DPM model was employed to simulate sediment particles, and the Finnie erosion prediction formula was combined to explore the erosion distribution characteristics of the dual pile foundation under different water flow velocities, sediment particle sizes, sediment concentration, pile wall roughness and arrangement type of double piles. The result show that the velocity distribution around the piles has a significant influence on the erosion distribution of the pile foundation. The erosion of the front pile is relatively sparse, mainly distributed on both sides of the water-facing surface, while the erosion distribution of the rear pile is more concentrated due to the influence of the wake zone of the front pile. With increasing water flow velocity, the overall trend of the maximum erosion rate of the pile foundation increases, but the rate of increase decreases after reaching a certain velocity. Moreover, as the sediment particle size, sediment concentration, and pile wall roughness increase, the maximum erosion rate of the pile foundation also increases. Specifically, for sediment particle size and pile wall roughness, when increased to a certain value, the rate of increase in the maximum erosion rate of the pile foundation decreases, while for sediment concentration, when increased to a certain value, the rate of increase in the maximum erosion rate of the pile foundation accelerates. With the increase of pile center distance, the maximum erosion rate of the front and rear piles of the tandem double pile increase, and the increase decreases gradually, while the maximum erosion rate of the left and right piles of the parallel double pile increase first and then decreases.

Keywords

dual pile foundation / erosion distribution / numerical model / maximum erosion rate / overall trend