Investigating the Causes of Landslides and Remedial Measures for The Selected Sections Along Ankober- Dulecha Road Upgrading Project
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Date
2020-07
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Addis Ababa University
Abstract
Currently, landslide is being a serious issue in Ethiopia, especially in association with different infrastructural expansions like a road. The frequent occurrences of this event become a cause for loss of life and different resources in the vicinity of these infrastructural works. Accordingly, it needs more attention in this regard for any geotechnical structures susceptible to failure by conducting an appropriate investigation, analysis and design for these structures so that appropriate remedial solutions should be established.
This thesis presents the investigation, analysis and establishment of possible remedial measures for the three selected failed cut slope sections located at station 2+550, station 7+130 and station 12+470 of the Ankober-Dulecha road project.
In this work, first characterization of the cut slope instability areas was conducted which includes the landslide location, geological interpretation of the area and engineering classification of the failed slope soil by conducting preliminary and detailed site investigation (testing). After the characterization of the failed cut slope, the analysis was carried out employing the finite element method using 2D PLAXIS software. In the analysis, both the undrained and drained or short term and long term analyses were conducted and it was found that the drained analysis is more critical for these cut sections. Finally, using the results of the investigation and analysis, the possible remedial measures were proposed at the respective landslide locations.
It was observed that the main reasons for the failure of cut slopes are the provision of a steep cut slope, presence of groundwater at shallow depth and spring water along the slope, presence of different residual bedding profiles and low shear stress resistance of the cut slope soil. Possible remedial measures were proposed at the respective landslide locations such as provisions of gravity retaining walls coupled with appropriate control (drainage )works.
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Failed cut slope, factor of safety, PLAXIS 2D, remedial measures, drained, undrained analysis