Slope Hazard Mapping of Swat Motorway

Abstract

The Swat Motorway, also known as the M-16 or Swat Expressway, is a 160-kilometrelong four-lane motorway and provincial controlled-access highway in the Khyber Pakhtunkhwa province of Pakistan. The major part of the motorway runs through the Peshawar basin plane while crossing Malakand ranges at some locations. Geologically, this region belongs to weakly metamorphosed rocks of the Mesozoic age and consists of schist, phyllite, and schistose marble. These rocks are excavated for the highway with a height ranging from a few meters to 80 meters. The Motorway section between Palai interchange and Tunnel 1 (near Chakdara interchange) is highly susceptible to slope failure/landslides. Landslides occurred from time to time and resulted in traffic diversion to another lane or completely closed for traffic. Therefore, a study is needed to investigate the slopes, prepare a slope hazard mapping and recommend different control measures. In this study, slope hazards mapping is generated for the sections from tunnel-1 to tunnel- 3 and its surroundings ,these sections are between Chakdara interchange to the Palai interchange. A reconnaissance survey and drone survey was conducted to identify different parameters of slopes (height, length, area, slope angle, Rock quality index, weathering grades etc). Based on the results of drone survey and different physical features a slope hazard mapping is generated using AgiSoft Metashape and QGIS software, which show low, moderate, high and very high slope risk areas. Different control measures are recommended for the high to very high slope failure areas to lower the risk of life and infrastructure.