Static model tests on mechanical behaviour of assembled multi-step cantilever walls

Abstract

An assembled multi-step cantilever retaining wall is a new type of light retaining structure, which can be quickly installed in situ and is suitable for high-fill earthworks. To investigate its mechanical behaviours fully to support practical analysis and design of the novel wall, a series of laboratory model tests is conducted for three-step cantilever walls retaining cohesionless filling under various strip surcharges on the top of the backfill. Test results indicate that lateral earth pressure on the highest-step wall member increases with the depth on the upper two-thirds segment of the wall stem, whereas it presents a multi-step polyline distribution mode on the lower two steps. Except for the highest-step wall member, the earth pressure on the upper part of each member stem shows some reduction effect due to shielding action of the upper heel plate inserted in the backfill. Horizontal displacement of the whole wall takes on a unimodal profile with relatively higher values at the middle height of the wall. Increasing the bench width is helpful to reduce the lateral earth pressure on the wall stems and setting up a shear key beneath the footing plate of the lowest-step member can reduce the wall displacement by up to 51%.