This paper employs three-dimensional parallel finite elements to assess the seismic response and resilience of various pile group configurations. The numerical model was verified in the literature through two large-scale shaking table tests. A parametric study was conducted to depict the influences of pile number (N), position within a pile group, pile nonlinearity, and frequency content on the seismic response in sloping liquefiable soils. The result showed that the importance of these factors on the analysis and design for the pile groups, while they are not considered in the current design codes including Japan Road Association (JRA) 2002 and American Petroleum Institute (API). Furthermore, the API method most likely underestimates P-y at shallow depths rather than numerical analysis results, while it overestimates at deeper burial depths. In addition, JRA code overestimates the monotonic soil pressure in the infinite pile group and underestimates it in the finite pile group. In other words, the difference between the computed soil pressure from JRA and the numerical model decreases with N. The asymmetry ratio (AR) is also important for the acceleration response, since AR decreases with N. Also, it has been shown that the seismic responses increase in corner piles with the N due to the increasing stiffness. Subsidence at the downslope side of the pile group and heave at the upslope side of the one occurs and increases with N. Nonlinear pile behavior increases maximum displacements, especially in central piles, while reducing internal forces in corner piles. Corner and side piles yield earlier, requiring middle piles to sustain greater forces under continued lateral spreading.
