A classification system for the assessment of slope stability of terrains along highway routes in Jordan

The establishment of comprehensive development plans, in general, and the proper selection of highway routes, in particular, require an assessment of landslides or instability hazards in the project sites. The frequent landslides that occurred along the routes of major highways in Jordan, and particularly along the Amman-Na'ur-Dead Sea highway and Irbid-Jerash-Amman highway, have substantially increased the cost of construction and caused a considerable delay in the completion of work. The study of many landslides that occurred in the last 25 years along the highway routes and in the sites of some major civil engineering projects in Jordan has led to the recognition of major factors that affect the stability of slopes, and thus the safety and economics of these projects. The geological formation, structural features, topographic characteristics, geometry, and climatic conditions were adopted as the basis for the classification of terrains in terms of their stability. Each factor has been assigned a rating to indicate its relative contribution to the overall stability according to engineering judgment and past experience. The areas have been classified into 5 groups according to their total stability rate. The simplicity, comprehensiveness, and accuracy are the main characteristics of the proposed classification. Its significance stems from its helpfulness as a guide to the geotechnical and highway engineers in assessing the overall stability of the alternative routes of proposed highway projects.