| Summary: | The Peace River region of Alberta, Canada is a highly active landslide area characterized by creeping landslides in weak lacustrine clays and silts. Much of the infrastructure for the region is built upon historical landslides and marginally stable slopes. Case studies of two landslides being selectively stabilized by pile walls in the Peace River region were conducted to investigate the relationship between the continued deformation of the downslope landslide material and the structural response of the pile walls. Two remote camera configurations were implemented, a photogrammetry technique at the first site and a two-dimensional digital image correlation (DIC) technique at the second site, to investigate the ability to use image based monitoring as a method of measuring large scale deformations downslope of these pile walls. The first study investigates a site that initially consisted of a cantilevered spaced pile wall that no longer sufficiently stabilized the landslide feature impacting a highway. A new, significantly larger tied-back tangent pile wall was constructed to address the ongoing landslide activity. Two years of post-construction monitoring have indicated excellent performance of the wall, and negligible deformations of landslide material. Due to the limited landslide movement, it was not possible to verify the photogrammetry monitoring technique. The second study examines a different landslide feature impacting a highway that was selectively stabilized with a pile wall. Three years of monitoring at this site indicates pile wall deformations up to 30 mm, and increases in ground anchor tie-back load of approximately 10%. Downslope landslide movements were measured with a high temporal resolution two-dimensional DIC technique using remote camera images. Deformation measurements ranging from 300 mm at a distance of 25 m downslope of the wall up to 1600 mm at a distance of 50 m downslope of the wall were recorded. Continued long term monitoring of these of selective stabilization walls will be important in assessing the service life of current pile walls and guiding efficient design of future pile walls. M.A.Sc.
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