Experiential and numerical investigation of the lateral bearing properties of drilled and post-grouted concrete pile and the its impact factors

Abstract

The drilled and post-grouted concrete pipe (DPG) pile consisting of a core pile and the surrounding grout layer is a prospective pile foundation proposed in recent years. In this paper, on the example of a pile group located in Suizhou, Hubei, China, the lateral bearing properties of the DPG piles and impact factors, such as the historical compression loads, the core pile prestress, the core pile wall thickness, the grout layer thickness, and the pile-head constrain conditions, were investigated with field tests and three-dimensional finite element analyses. For the analyzed case, the results show that historical compression loads would increase the pile-head lateral displacement by 125.8–287.3% and decrease the lateral bearing capacity by 32.4%. The core pile prestress prevents the pile shaft from cracking, reduces the flexure deformation of pile shaft, and improves the lateral bearing capacity of the DPG pile by 12.9%. The effects of varying the core pile wall thickness on lateral bearing characteristics are negligible. However, the thickness of the grout layer increases from 0 to 100 mm leading to a 27.2% increase in lateral bearing capacity and a 35.3% decrease in pile shaft bending moment. Additionally, constraining the pile-head rotation would improve the lateral bearing capacity by 60.9% and decrease the pile-head displacement by 68.4%.