Analytical model for laterally loaded pile groups in layered sloping soil

Abstract

The historic canal wall structures in many Northern European cities have been built as masonry walls on a timber deck founded on timber piles. For analysis of the resistance of those structures and assessment of their remaining service life, suitable and accurate calculation models are needed. Thereto an analytical method was developed for modelling laterally loaded pile groups in layered sloping soil. In the proposed method, the bending of a pile, which is subjected to a lateral load and axial load, is described by a beam on a Winkler elastic foundation in which the soil behaviour is represented by a series of independent p-y springs, idealized with a bilinear elastic-perfect-plastic approximation. The plastic limit was computed with Brinch Hansen ultimate soil resistance and the elastic soil response by the Ménard stiffness. The plastic limit was corrected for each depth, based on the reduction of the passive soil wedge due to pile group effects and the presence of a sloping surface. The analytical model was calibrated and validated with three field experiments, one full-scale lateral load test of a 3 × 5 pile group in soft clays and silts (Snyder, 2004), one full scale lateral load test of a single pile located on a slope in layered soils (Mirzoyan, 2007) and one small scale lateral load test of a single pile located near a slope in sand (Abdelhalim et al., 2020). The proposed method can adequately predict bending moment distributions and pile deflections and in addition, a good consistency between the analytical model and experimental tests was observed. The method is very fast, making it suitable for probabilistic, Monte Carlo type, simulations and reliability updating to determine the probability of failure of quay walls or other structures with horizontally loaded piles.