Slope Instability Assessments And Mitigation Measures On Road Failure: In Case Of Addisu Gebeya To Sululta Road

Abstract

The aim of this research study was to investigate the geotechnical properties of various types of soil, assess the slopes' stability, and of ering suggestions for mitigation measures to deal with the slope stability issues. Fieldwork, laboratory tests, and slope stability studies are some of the approaches/methods employed. This research was conducted on the road from Entoto check point to Dilber area since this road is used since it is the Addis Ababa - Bahirdar connecting route and has traf ic flow every day. Research was done by selecting three critical slope sections and conducting laboratory tests and slope stability analysis using both limit equilibrium method (Slope/W) and finite element method (Plaxis) in order to get factor of safety and observe the dif erence between the two methods. The laboratory tests were conducted using standards and the conducted tests are natural moisture content, .Specific gravity, Atterberg limit, Grain size distribution, Direct shear test, Free swell test and Compaction in order to characterize the soil material gathered. The software analysis by Slope/W resulted a factor of safety of 1.281, 1.415, and 1.352 respectively for the three critical sections and the software Plaxis resulted a factor of safety 1.237, 1.361 and 1.14 respectively. The possible causes for future instability can be due to the presence of the clay soil that is being subjected to intense rainfall for long period throughout the year. Mitigation measures were also suggested in this research which are geometric modification, providing proper drainage, providing retaining structures such as Gabion walls, remove unstable sections and increase vegetation coverage in order to avoid future problem.