Yield acceleration and permanent displacement of a slope reinforced with a row of drilled shafts

highlights
• A method for estimating yield acceleration of a drilled shafts/slope system under a seismic excitation is presented.
• Permanent displacement of a slope reinforced with drilled shafts under an earthquake excitation can be estimated using the Newmark's method.
• A total of seven cases were presented to show the validity of the proposed simplified method.

In this paper, a method for estimating yield acceleration of a slope reinforced with a row of equally spaced drilled shafts under a seismic excitation is presented. The method is based on a concept of soil arching due to rigid inclusions of drilled shafts on slope, which in turn reduces the driving force on the down-slope side of drilled shafts. Considering soil arching effects and earthquake-induced inertia forces, a limiting equilibrium based formulation was derived. A computer program was coded to allow for calculations of yield acceleration of a drilled shafts reinforced slope with complex slope geometry and soil profiles. Once yield acceleration is determined, then Newmark's method can be evoked to estimate permanent displacement of a slope reinforced with a row of drilled shafts under an earthquake excitation. A total of seven cases were presented to show that the proposed Newmark type calculation is adequate when compared to 3-D finite element analysis results.