Design and Construction of Concrete Pile Retaining Walls for Slope Stabilization along a River Valley Trail in Edmonton, Alberta

ABSTRACT: A landslide occurred along the North Saskatchewan River’s south valley slopes during the summer of 2020, causing the collapse of three timber retaining walls and damaging an important shared use trail southwest of the Capilano Bridge in Edmonton, Alberta. The failed slopes required stabilization involving the construction of two parallel cast-in-place concrete pile retaining walls, and reconstruction of the above-ground retaining walls and trail, in order to reopen the shared use trail for cyclists and pedestrians. A geotechnical investigation was carried out to evaluate the overall slope failure and provide adequate information for the trail rehabilitation. This involved slope stability analysis and finite element analysis using PLAXIS 2D. The results of these analyses were then used in structural analyses to design the twin buried concrete pile retaining walls. Slope movements before and during construction were monitored using slope inclinometers. The management of construction risk was also supplemented by survey monitoring of slope stakes used as surface monuments.