A Calculation Method for Stress and Deformation of Loess Slope Retaining Piles Considering Pile-Soil Relative Displacement

[Purposes] This work is carried out to address the significant deviation between assumed and measured earth pressure distributions in loess slopes. [Methods] The deformation and stress laws of anti-slide piles supporting loess slopes were investigated through theoretical analysis and field experiments, a calculation method for pile deformation considering pile-soil relative displacement was proposed, and further analyses of relevant influencing parameters were conducted. [Results] Comparative results show that the values obtained from theoretical model proposed in this study align more closely with measured values, demonstrating the applicability of this model in the design of retaining piles for loess slopes. The analyses of influencing parameters reveal that under the same soil lateral displacement pattern, the pile deformation and bending moment are directly proportional to the soil lateral displacement, and the incremental soil lateral displacement exerts an equal influence on both pile displacement and bending moment. Specifically, when the free soil displacement increases by 125%, both the pile displacement and bending moment increase by 125%. The pile deformation and bending moment are minimal under an inverted triangular distribution, maximal under a rectangular distribution, and intermediate under a trapezoidal distribution. The bending moment of the pile gradually decreases as the foundation coefficient of the soil above the sliding surface increases, and gradually increases as the foundation coefficient below the sliding surface rises. The bending moment and displacement at various depths of the pile show a linear correlation with pile stiffness, with the effects being most pronounced at the sliding surface where the pile undergoes significant bending and displacement. The research findings provide valuable insights for the design of retaining piles in loess slope support systems.