Part D: Slope Management
Slope management is a critical activity for most road authorities, but particularly those with a road network that traverses hilly or mountainous terrain. Computerized road management systems are now commonplace on high-volume roads (e.g. Paige-Green 1997; Robinson et al. 1998; McPherson & Bennett 2005; Russell et al. 2008) with in-built deterioration and cost-benefit models to inform the user as to what length of road needs to be upgraded, by how much and when. Although slope management systems have been developed (e.g. Heath et al. 1995; Heath & McKinnon 1996; Bujang & Jamaludin 2005; Lee et al. 2006; Kwon & Baek 2010; Leyland 2010), these are relatively uncommon on low-volume roads. A significant amount of asset data are required to be collected in the development of road and slope management systems; on low-volume roads it is likely to be most prudent to focus on the difficult areas first, that is, those where road assets are most at risk from slope instability.
Slope management encompasses all factors that affect the stability of a slope, whether natural or man-made, and therefore also includes road and slope drainage, erosion protection, retaining walls and river training works where appropriate. Consequently, a broad range of experience is required for effective slope management with skills in the following areas:
landslide recognition and engineering geology;
risk assessment for prioritization of sites;
Figures & Tables
This book provides a complete guide to the study, design, construction and management of landslide and slope engineering measures for mountain roads, with an emphasis on low-cost. The geographical focus of the book is on the tropics and sub-tropics, but is also highly relevant to other regions where heavy rain, steep slopes and weak soils and rocks combine to create slope instability. The causes and mechanisms of landslides are described, and the hazards they pose to mountain roads are illustrated. Methods of desk study, field mapping and ground investigation are reviewed and illustrated, with an emphasis on geomorphological and engineering geological techniques. The design and construction of alignments, earthworks, drainage, retaining structures, the stabilization of soil slopes and rock slopes, and the control of erosion on slopes and in rivers and streams are covered. Slope management as part of road maintenance and operation is reviewed, and procedures for risk assessment and works prioritization are described.