Simplified Seismic Stability Analysis of Piled Inhomogeneous Soil Slopes

Due to the discontinuity of soil properties in inhomogeneous slopes, the potential slip surfaces are not smooth curve surfaces, which makes great challenges for the existing rigorous theoretical methods for stability analysis of the slopes reinforced with piles under seismic conditions. By utilizing the discrete kinematically admissible failure surface to establish a non-smooth slip surface, pseudo-static approach to simulate the seismic action, and energy balance relationship considering the pile axial forces to keep the basic equilibrium principle, we derive a closed-form solution to resolve this problem. Analysis results of some examples show that the proposed method can provide more conservative pile shear forces than the existing theoretical values with a relative error of about 8% under strong earthquake. The factors such as pile parameters, slope parameters, soil properties, and seismic acceleration coefficients have important effect on the pile shear resistance. The pile shear force is nonlinearly increasing with the slope angle, horizontal seismic acceleration coefficient, and thrust application point coefficient. However, it decreases slightly with the increase of the pile spacing owing to the pile axial force, which also has an influence on the relationship between the pile location and the shear force. Soil inhomogeneity can significantly change the pile shear force, but cannot generally influence the variation pattern of the shear force with these factors. The proposed method can serve as a helpful tool for the design of piled inhomogeneous soil slopes.