Landslide Risk Assessment and Preventive Measures of Selected Locations in the Rangamati District, Bangladesh

Abstract

Detecting landslides and unstable slopes is one of the most crucial responsibilities in the emergency response to resist landslides. Having a wide range of hilly terrines in the southeast region of Bangladesh, the risk of landslide disasters is becoming a critical issue. In Chittagong, especially in the Rangamati hill tracts, there have been several losses of life and property due to landslides in the recent past. This research attempts to evaluate the landslide risk in Rangamati hill tracts and provide suggestions to mitigate the landslide hazard by modifying the hill slope. Soil specimens from different hill locations were collected from three areas in the Rangamati district. Several laboratory experiments were conducted to determine the soil properties, and 2D slope stability analysis using Bishop's simplified method was used to evaluate the landslide potential. Different preventative measures, for example, soil nailing, anchors, and cutting slopes like stairs, are also implemented to mitigate the landslide potential by increasing the slope stability was assessed and suggested. Weighted Overlay Model (W.O.M.) was implemented for the Landslide Susceptibility Analysis in ArcGIS to confirm the potential hazard in the study areas, and hazard maps were suggested based on the slope stability results and current slopes in Rangamati. The slope stability analysis of the three spots showed that spot 3 is the most vulnerable spot, which had a low factor of safety value. Even with different mitigation techniques, spot 3 showed a lower factor of safety value, which was verified with the Weighted Overlay Method. It was also seen that among the mitigation techniques, anchoring the slopes is the most effective one that drastically increases the factor of safety value.