Analysis of PV Drains for Mitigation of Seismically Induced Ground Deformations in Sand Slopes

Abstract

Prefabricated vertical (PV) drain arrays have been proposed as a minimally intrusive technique for mitigating seismically induced ground deformations in sandy liquefiable slopes. This paper describes the representation of individual PV drains as line elements within a finite-element program. The elements can represent laminar or fully turbulent discharge regimes, based on classic Darcy-Weisbach pipe flow, as well as fluid storage above the water table. Two-dimensional, plane strain simulations of coupled flow and deformation are performed using the proposed PV drain elements, with equivalent permeability properties for the surrounding soil mass, and a constitutive soil model describing the nonlinear effective stress-strain behavior of the sand. The numerical predictions are evaluated through comparisons with pore pressures and deformations measured in a centrifuge model test. The results highlight the role of the PV drains and their discharge characteristics in controlling deformation mechanisms.