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IJSTR >> Volume 8 - Issue 3, March 2019 Edition

International Journal of Scientific & Technology Research  
International Journal of Scientific & Technology Research

Website: http://www.ijstr.org

ISSN 2277-8616

Effects Of Rainfall Patterns On The Stability Of Upper Stack Of Open Pit Slopes

[Full Text]



Wang Yiming, Trevor Siame, Victor Mwango Bowa



Rainfall Pattern; Matric Suction; Pore water Pressure; Safety Factor; Slope Failure



Since mining started in 2008, Lumwana (Malundwe) Open Pit has experienced slope failures in the saprolite formation in the upper stacks of the pit’s slope, during rain seasons. Comprehensive integrated studies have been performed to investigate parameters controlling the stability of the upper stack of Lumwana (Malundwe) open pit due to rainfall pattern. The study results reveal that the saprolite soils’ matric suction increases with the decrease in rainwater content in the saprolite soil, leading to an increase in shear strength of the slope for the upper stacks. Once shear strength is sufficiently increased , the saprolite soil slope become sufficiently stable in dry season. During rain season, the negative pore pressure tend to reduce towards zero and even become positive with rising water table. Such a change in pore water pressure causes a decrease in the shear strength. Once the shear strength is sufficiently decreased , the upper slope becomes instable that slope failure may occur. Generally, the events of rainfall gives an impact on the degradations of the safety factor of upper stack of Lumwana (Malundwe) open pit.



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