Investigation of active earth pressures and failure mechanism of retaining walls with a relief shelf

摘要

Various studies of retaining walls with relief shelves tend to rely on the proposition of reducing soil pressures behind the wall, according to the location and the width of relief shelf. The previous numerical studies did not predict the optimum reduction rate of earth pressure and the shape of failure mechanism. The finite-difference code fast Lagrangian analysis of continua is used to evaluate the active earth pressure behind a retaining wall with one relief shelf placed at different levels with a variable width. The soil behind the wall is modelled by an elastoplastic constitutive model with a Mohr-Coulomb yield criterion. The effects of soil non-associativity as well as the interface of soil-wall and relief shelf-soil are investigated. The reduction of earth pressure is estimated by the rate R, defined as the ratio of the reduced active thrust to the total active thrust of a wall without a relief shelf. The rate R is evaluated numerically and by using Klein's solution. The obtained results enable determination of the appropriate position and width of the relief shelf to evaluate the optimum values of R.