R. Ulusay et al., APPLICATION OF A ROCK BUTTRESS IN THE DESIGN OF SLOPES OF A STRIP COAL-MINE ADJACENT TO A HIGHWAY, Canadian geotechnical journal, 30(3), 1993, pp. 391-408
Eskihisar open pit mine, located at Yatagan, southwest Turkey, produce
s thermal coal for a power generating plant. As mining of strips advan
ced southwards, instability appeared to be highly critical due to the
movements in the southeast wall slopes adjacent to the state highway r
unning parallel to the pit boundary. This situation called for an imme
diate response to initiate a detailed geotechnical investigation progr
am and to redesign the pit slopes. This paper outlines the most probab
le mode and mechanism of instability along the southeast wall, as well
as field and laboratory studies, results of back analysis, discussion
of the data requirements, and results of slope stability analyses per
formed to ensure adequate overall stability. The studies revealed that
the most critical failures may occur along two or three planar surfac
es, by combination of fault, bedding plane, and localized strata steep
ening adjacent to the fault. in multiplanar failure mode controlled by
faulted blocks. The stability is sensitive to changes in length of th
e lower part of the basal sliding surface, as well as to the configura
tion and shear strength of black and highly plastic underclay. The eff
ects of a buttress of intact rock and slope flattening on the stabilit
y are compared and discussed.