Structural mitigation of landslides is increasingly necessary where existing geologic hazards intersect with displacement-sensitive infrastructure. Conventional shear pile systems require passive resistance be developed by displacement of the landslide. Where displacement of the landslide or structural system is undesirable, anchored shear piles (ASP) can be used to develop full-depth restraint of large landslide masses with limited post-construction deformation. No published standard for the design of such a system exists, and a typical 'lateral-loading-of-pile' approach can yield inefficient or even unconservative designs. This paper presents a design approach for landslide mitigation through the use of high-capacity ground anchors integral with cast-in-place concrete shear piles. ASP take advantage of increasing soil strength with depth to apply much larger ground anchor loads at the surface than could obtained through ground anchors on bearing blocks. In addition, construction of an ASP system can provide full-depth resisting force to a landslide, without the risk and right-of-way impacts of large open-cut excavations. A recent case history with instrumented structural elements will be discussed. An outline of the design method, construction considerations, and performance of an ASP system is presented. Inclinometer data is presented to outline in-situ performance, and to discuss the applicability and accuracy of design predictions.
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