Seismic Bearing Capacity of Strip Foundation Embedded in c-ϕ Soil Slope

Abstract

In this paper, seismic bearing capacity factors for shallow strip foundations embedded in homogeneous c-ϕ soil slopes are presented. A numerical study is performed using finite-element limit analysis (FELA) with lower bound (LB), upper bound (UB), and 15-node (15N) mixed Gauss element formulations. The pseudostatic approach is used to consider the seismic action on both soil and foundation. The study explores the influence of different governing parameters, namely slope angle (β), angle of internal friction (ϕ), foundation embedment depth ratio (D/B, where D = depth of the footing from slope surface; and B = width), and horizontal seismic coefficient (αh), on the ultimate bearing capacity of the embedded strip foundation. The bearing capacity factors Ncs and Nγqs decrease rapidly with an increase in β and αh, and an increase with D. Compared with Ncs, the factor Nγqs is more sensitive to the changes in β, ϕ, D/B, and αh. Based on the results obtained from the study, a set of design charts and a simple spreadsheet-based tool (SBCSFES) are developed.