The Effect of Input Frequency on Dynamic Soil-Structure Interaction of Levees with Cutoff Walls

A large number of levee systems have embedded cutoff walls incorporated into their design in order to guard against instability due to excessive under and through seepage. Recent studies have indicated that these systems are vulnerable to seismic hazards and have raised the issue of seismic design of levees with cutoff walls. The seismic response of levees with cutoff walls is not well understood and this paper intends to investigate how the presence of an embedded cutoff wall affects the response of a levee to ground shaking. A fully nonlinear, dynamic, 2D parametric analysis is conducted using the finite difference modeling software FLAC. A variety of levee profiles, with steel sheet pile cutoff walls are investigated. In order to systematically investigate the dependence of levee response on ground motion frequency content and amplitude, the profiles are subject to a range of Ricker wavelet input motions. The resulting site amplification effects and topographic aggravation effects are observed and compared to similar levee profiles without cutoff walls. Also, the effects of the cutoff wall presence on the accelerations and strains within the levee and foundation are discussed.