Erodibility of soils in rural roads


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Ngezahayo, Esdras (2020). Erodibility of soils in rural roads. University of Birmingham. Ph.D.

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Rainfall is a significant factor in the erosion of unpaved roads. If inappropriate soils are used for construction, even a short rainfall duration can render poor conditions on unpaved roads. Rainfall has a twofold effect on the surface. The impact of raindrops can result in the dislodgement of soil particles; while subsequent water flow transports the loosened soils. A laboratory investigation was undertaken to study erodibility of granular and clayey soils that may be used for the construction of unpaved roads. The study aimed at identifying the suitability of soils that can be used for the construction of erosion resistant unpaved roads. Those roads are indispensable for sustainable growth of rural areas in developing countries. Compacted samples were subjected to simulated rainfall intensities of 30 mm/hr, 51 mm/hr and 68 mm/hr for 30 minutes over a two-day period. The eroded soil quantities contained in the run-off were measured at intervals of 5 minutes. The effect of erosion on the surface particles was assessed using photographs. Erodibility decreased with increases of both the clay fraction and the size of the granular particles. Moreover, erodibility increased with the increases of the rainfall intensity, slope gradient and length. Smaller particles eroded faster than coarser particles. At the surface, the number of soil particles reduced, whilst their size increased with the increasing rainfall duration. The runoff coefficients increased with the increasing clay content, slope gradient, and higher rainfall intensity. Both the erodibility and the runoff coefficients reduced in the second-day experiments.

Type of Work: Thesis (Doctorates > Ph.D.)
Award Type: Doctorates > Ph.D.
Licence: All rights reserved All rights reserved
College/Faculty: Colleges (2008 onwards) > College of Engineering & Physical Sciences
School or Department: School of Engineering, Department of Civil Engineering
Funders: Other
Other Funders: Commonwealth Scholarship Commission in the UK
Subjects: T Technology > TA Engineering (General). Civil engineering (General)
T Technology > TE Highway engineering. Roads and pavements
T Technology > TF Railroad engineering and operation


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