Numerical Investigation of Inclined Piles under Liquefaction-Induced Lateral Spreading

Inclined piles have been widely applied as one of the countermeasures against large lateral spreading induced by soil liquefaction during earthquakes. However, the unsatisfactory performance of inclined piles in past events has impeded their application in seismic areas. To elucidate the performance of inclined piles when subjected to lateral spreading induced by soil liquefaction, numerical analyzes were performed using the OpenSees framework. For this purpose, a comprehensive three-dimensional finite element model was developed. Interface elements were used between the soil and the pile to account for the friction and gapping mechanisms. A multi-yield-surface plasticity constitutive relationship for sand was adopted to simulate the soil liquefaction behavior. Based on the proposed numerical model, parametric analyzes were conducted to investigate the influence of various factors on the behavior of inclined piles, including the raked angle of the pile, the ground slope, the soil profile, and the amplitude of the input motion. The response of the system indicates that inclined piles can behave better than vertical piles in decreasing soil deformation and the cap response. The influences of the investigated factors are highlighted to adopt the appropriate pile inclination in laterally spreading ground and maximize the advantages of using inclined piles.