Pseudo-dynamic lateral earth pressure on stabilizing piles in sandy slopes considering arching effect

It is essential to accurately estimate the earthquake-induced earth pressure for reliable seismic design of stabilizing piles in slopes. Despite the availability of various analytical methods for estimating the pressure behavior of piles, they generally neglect the arching effect and are inapplicable for earthquake loading conditions. Therefore, a novel analytical approach is presented in this study to calculate the seismic lateral earth pressure on piles by considering the arching effect in homogeneous cohesionless soils. Variations in seismic accelerations within the sliding body are explicitly considered using the pseudo-dynamic method. This is then combined with limit equilibrium theory for characterizing the seismic sliding wedge, and with principal stress rotation theory for solving the active earth pressure on inter-pile soils under harmonic excitation. An improved soil arching model is developed to realistically represent arch geometry and to quantify the load transfer between piles and the inter-pile soils. It is demonstrated that the presented approach accurately predicts the depth dependency of seismic lateral earth pressure and its growth with increasing seismic intensity, closely matching experimental and numerical measurements. When compared with the conventional pseudo-static method, it gives a more meaningful solution due to consideration of the spatial-temporal effects of earthquake input, particularly under conditions of significant amplification effect. Meanwhile, the variability of spatial arching behavior can also be accommodated by the presented approach through minor modifications to the governing equations of arch geometry. This study facilitates the preliminary assessment of the dynamic load response of piles in slopes.