The use of drilled shaft concrete piles is generally not a widespread method of stabilization of landslides along Alberta Highways as a result of perceived high costs and the uncertainty of performance of these structures in the long term. However, over the last thirty (30) years, the use of drilled shaft piles has been the preferred method of stabilization of various sites where conventional methods were not feasible either because of site constraints or not considered appropriate. This paper presents a case history of a roadway embankment slide for which the most appropriate remedial measure was determined to be the use of a tie-back drilled shaft concrete pile retaining wall as a result of the deep seated nature of the slide, inability to relocate the roadway, and concerns using a toe berm. Stabilized in 1997, the roadway and pile wall are still performing satisfactorily despite some observed roadway undulations and movements of the sideslope behind the pile wall. This paper addresses the details of the site and slide activity, the judgments exercised in deciding the locations and depth of the concrete piles, and the design and construction of the pile wall retaining system.
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