Application of tyre bales to slope failure repair

Abstract

Landslides take a variety of forms including slides, flows, falls, topples and spreads. Many landslides require a degree of remediation to ensure that infrastructure and property are left in an acceptably safe condition. The many forms of remediation available include the removal of loose material (often also involving its replacement with more competent material), stabilisation of the remaining material and the complete engineering reconstruction of an area of the slope. In some cases quite large volumes of failed material may be removed and replaced with competent material. In general, failures that produce large holes will tend to fall into the category of slides be they circular, translational or wedge failures. However, flows can also excavate quite large gully-shaped volumes during their erosional phases. The main requirements of the fill material are usually that it should be free-draining and high friction, and should prevent internal and external migration of material in order to avoid further build-up of water pressures. Typically, rockfill is used and plastic materials are to be avoided. Tyre bales are a relatively new form of material that satisfy the criteria for such fill. This paper describes the key features of tyre bales in the context of slope failure remediation. Types of failure in which tyre bales might be successfully used are discussed, as are issues in relation to drainage, excavation boundary conditions and placement and alignment of bales. Successful applications are also described, including the results of an analysis of a slope failure repair using tyre bales.