Influence of Wall Flexibility on Seismic Earth Pressures in Vertically Homogeneous Soil

Abstract

Solutions are formulated for seismic earth pressures acting on vertical flexible walls with the top and bottom constrained by discrete elastic stiffness elements (top constraint representing a structural constraint, bottom constraint representing foundation stiffness). Solutions are formulated using the Winkler assumption and correspond to shear waves propagating vertically through homogeneous soil. Earth pressures decrease as wall flexibility increases. Rotational and translation constraints at the top and bottom of the wall also contribute to mobilization of seismic earth pressures. Current standard-of-practice procedures are based on limit analysis methods that do not consider the influence of frequency, wall flexibility, structural constraints, or soilstructure interaction (SSI) in general. The proposed approach is more robust because wave propagation effects are considered and seismic earth pressures result from the product of relative wall-soil displacements and stiffness at the wall-soil interface.

Winkler Stiffness Intensity for Flexible Walls Retaining Inhomogeneous Soil

“…The trends are approximately constant for 34 values larger than about two, indicating that the wall is essentially rigid in this range. Figure 6 also shows comparison with the analytical solutions formulated by Younan and Veletsos (2000) and Brandenberg et al (2017b) for flexible walls retaining homogeneous soil. The Younan and Veletsos (2000) approximate analytical solution applies for the seismic earth pressure acting on flexible walls retaining uniform soil under static conditions.…”

“…The numerical method used in this paper produces the same response as the analytical solution proposed by Younan and Veletsos (2000). The Brandenberg et al (2017b) solution uses the Kloukinas et al (2012) expression for the Winkler stiffness intensity and it models the wall as a Euler-Bernoulli beam. Differences between the results presented here and those from the aforementioned previous analytical studies may arise from mesh discretization errors in the finite element solutions.…”