Numerical Investigations of Pile Group Foundations under Different Pile Length Conditions

Abstract

At present, group pile foundations with the same length of pile base are used basically in large-scale slope group pile foundation projects. Therefore, pile group foundations with piles of different lengths have a certain research value. Based on the actual working condition of a bridge group pile foundation, a similar model is established, which is imported into the FLAC3D 6.0 finite element software package together with the processed relevant data, and the bearing performance of the cap-group pile foundation under the joint action of axial uniform load and landslide thrust is studied. The study shows: under the same bearing conditions, the settlements of group pile foundations with the same pile length and different pile lengths are similar, and the settlements of the rear row of piles is significantly higher than those of the front row of piles; the settlement of the cap platform in the area without backfill soil is different from that in the area with backfill; the front row of piles has some negative displacement within the range of 10 m below the equivalent sliding surface, and the displacement of the pile body from the back row of piles to the front row of piles increases linearly; the maximum bending moment of the foundation pile is at the position of the gravel soil layer, and as the load changes, the position of the maximum bending moment point will also change; the plastic zone of the uppermost gravel soil layer in the slope model has the tendency of penetration, but it is truncated by the group of piles, and the factor of safety is 2.4 in the case of 100 KN axial uniform load, this structure tends to be stabilized, and the factor of safety decreases with the increase in the load. The analysis of the bearing characteristics of group piles under horizontal and vertical loads and its related conclusions can be used as a reference for related engineering design.