Two-pile foundation supporting a bridge structure near a clay slope is subjected to significant lateral loads, where its capacity is diminished by the combined group and slope effects. This paper develops an analytical method to predict the lateral response by integrating pile-pile and soil-pile interactions. The evolution of the soil-bearing mechanism around the two-pile is elucidated by considering the group and slope effects. Five failure wedge models and four evolution processes are introduced to evaluate the ultimate soil resistance of shallow regions, capturing the reduction in ultimate soil resistance. Additionally, by integrating the ultimate soil resistance obtained from the deep-region full-flow failure, a p-y curve model is developed to characterize the lateral response of two-pile foundation under lateral load. The comparison with the existing literature cases and a series of finite element results indicates that the proposed method has strong validation. Finally, the influence of group and slope effects on the bearing characteristics of two-pile under different centre-to-centre pile spacing, slope angle and near-slope distance is analyzed. Notably, the analysis reveals that center-to-center pile spacing and near-slope distance exert a more pronounced impact on lateral bearing capacity compared to changes in slope angle.
Qin et al. (Sun,) studied this question.