Structural Aspects of the Stabilization of Ten Mile Slide-PPT Presentation

PPT Presentation

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The Ten Mile Slide stabilization project addressed a moving slope threatening transportation infrastructure, including CN Rail and a road. Its main design and construction challenge was accommodating continued slope movement while the retaining system was being built.<br /><br />The stabilization system combined upslope rows of tie-back anchors with a retaining wall made of composite and concrete piles, walers, and a pile cap. Composite pile steel shells acted as temporary structural keys to slow movement; as concrete within the shells hardened, they provided added resistance and allowed the concrete piles to be installed.<br /><br />Designers used limit-equilibrium analyses to guide the design, then applied FLAC finite-difference modelling to examine the critical slope section and simulate construction stages and anticipated movements. A three-dimensional RFEM model assessed the piled wall and its components. Results from the two models were reconciled to account for differences in how they represented anchor forces and soil pressures. The analyses also considered downstream slope sloughing, anchor resetting, and a 1-in-475-year earthquake event.<br /><br />Construction and modelling were organized into sequential stages, including anchor installation and tensioning, pile-wall construction, excavation and backfilling. About a year after completion, material from the downslope Tunnel Earthflow began to slough. The project involved the BC Ministry of Transportation and Infrastructure, Xaxli’p First Nation, engineering consultants, and specialized construction and piling contractors.

Keywords

Ten Mile Slide

slope stabilization

retaining wall

tie-back anchors

composite piles

finite-difference modelling

FLAC

RFEM

earthflow

transportation infrastructure