Abstract
Earth slopes stability analysis is important in the design and construction of earth dams under different loading conditions. Several factors such as difference in water level or rapid drawdown in the reservoir, right after construction, and steady - state seepage may result in instability of Earth Dams for all possible combinations. In this study, three scenarios were evaluated for the Gbeni Earth Dam (GB3) at Sierra Rutile Mining Company in Sierra Leone. It is a zoned earth-filled embankment dam with respective upstream and downstream slopes of 1:3 and 1:2, having a horizontal sand blanket downstream. The upstream slope was subjected to both rapid drawdown in the reservoir of the earth dam and end of construction condition when there is no water present in the reservoir, whilst the downstream slope was assessed for steady seepage and end of construction conditions. The shape of the critical slip surface of both slopes was evaluated using a circular failure surface. The objective of this study was to assess the stability of these slopes under the above conditions using traditional analysis according to the theory of limit states and safety factor in GEO 5 software and its subprograms. The level of water on the upstream and downstream banks, the geotechnical properties of soil materials and boundary conditions of the dam were used as contribution variables and safety factors as the desired output. The study found out that the factor of safety against sliding of the upstream slope marginally drops within the short period after the start of rapid drawdown of water in the reservoir of the dam. Also, the downstream slope was found to be more stable under steady seepage. This accounts for the uncertainties involved in the strength of material, pore pressures in impervious clay core material, and long-term loading condition.
Highlights
Sierra Rutile Mining Company is one of the oldest mining companies in Sierra Leone that relies on dams for various mining processes
Consideration was given to all loading conditions which may result in instability of the GB3 water storage earth dam
In this slope stability analyses of the GB3 Earth Dam, the effective stress state soil properties were used, and the most critical slip circle centre according to five analysis methods was considered
Summary
Sierra Rutile Mining Company is one of the oldest mining companies in Sierra Leone that relies on dams for various mining processes. The company has well over thirty dams, ranging from earth-filled to tailings that have existed for many years. Gbeni Earth Dam is the third water storage dam within the Gbeni area, one of the company’s mining environments. The dam is 300m long, 100m wide and 18m high with 1:3 upstream and 1:2 downstream slopes. A 25m wide and 100m long horizontal sand drainage blanket was incorporated at the downstream grade in order to handle seepage of water within the dam. GB3 Earth dam was designed to handle an estimated volume of 5,386,000m3 of water
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: International Journal of Materials Science and Applications
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
