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

Assembled multi-step cantilever retaining walls is a new type of light retaining structure, which can be quickly installed in situ and suitable for high fill earthworks. In order to investigate its mechanical behaviors fully to support practical analysis and design of the novel wall, a series of laboratory model tests are 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 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. The lateral earth pressure on the wall obtained by numerical simulation via FLAC3D is consistent with the measured one in terms of the whole variation tendency. 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 shear key beneath the footing plate of the lowest-step member can reduce the wall displacement by up to 51%.