Field Testing and Numerical Analysis of Supporting Performance of Oblique Piles Used in Pit Excavation

To explore the supporting performance of oblique piles (OPs) used in pit excavation, a field test was performed at a foundation excavation using OPs with various inclination angles. Then, numerical models using the finite-element method were established and validated on the basis of the field test result. A novel arrangement of oblique-vertical alternating piles (OVAPs) was proposed as the retaining structure for excavation. The displacements of the pile top, internal forces of the pile body, earth pressures on the pile body, and soil deformation were observed and studied. The results indicated that both pile inclinations and arrangements had an effect on the supporting performance of oblique piles. Furthermore, four effects were summarized to explain the advantages and working mechanisms of OP and OVAP arrangements used in retaining structures. Finally, a force analysis of oblique supporting piles in the foundation pit was conducted and a simplified formula was derived and applied to calculate the bending moments of pile bodies under different working conditions.