A Field Study on the Stability of Road Cut Slopes in Nepal

Robson, Ellen; Pradhan, Samprada; Toll, David

Abstract

The density of Nepal’s road network has more than tripled in the last three decades. This growth has been rapid, extensive and in places haphazard, occurring on both the local and strategic road networks, and has resulted in the widespread failure of road cut slopes throughout Nepal. To further understand this effect, field assessments were carried out along roads of different governing grade in Nepal, focusing on the stability of cut slopes and effectiveness of stabilisation measures adopted. This paper summarises the key findings of this study. Although there are multiple guidelines from the Government of Nepal with recommendations on the design and construction of road cut slopes and stabilisation measures, the cut slopes were commonly found to be excavated to steeper inclinations than advised in these guidelines. The cut slopes that were steeper than the advised inclination remained stable before the monsoon, but often failed during the monsoon season due to rainwater infiltration that leads to dissipation of soil suction. Field observations also revealed that the roadside drainage was either not implemented or was blocked. The retaining walls were found to be designed to the same geometry, despite differences in cutting heights and slope materials. This resulted in overturning, bulging, and cracking of the walls. Based on the findings of this study, it is clear that to build resilient road infrastructure in Nepal, the road cuttings need to be excavated according to rigorous engineering guidelines, and standards for the practice of quality assurance need to be implemented.

Citation

Robson, E., Pradhan, S., & Toll, D. (2023, March). A Field Study on the Stability of Road Cut Slopes in Nepal. Presented at Geo-Resilience 2023, Cardiff University

• Presentation Conference Type: Conference Paper (published)
• Conference Name: Geo-Resilience 2023
• Start Date: Mar 28, 2023
• End Date: Mar 29, 2023
• Acceptance Date: Mar 1, 2023
• Online Publication Date: Feb 28, 2024
• Publication Date: Feb 28, 2024
• Deposit Date: Feb 29, 2024
• Publicly Available Date: Mar 1, 2024
• DOI: https://doi.org/10.53243/Geo-Resilience-2023-1-8
• Keywords: Slope Stability, Road cuttings, Nepal, Retaining Walls, Suction
• Public URL: https://durham-repository.worktribe.com/output/2290346
• Publisher URL: https://www.issmge.org/publications/publication/a-field-study-on-the-stability-of-road-cut-slopes-in-nepal