Stability analysis of barriers protecting underground mine entries in coal slurry impoundments

摘要

Stability analysis of earth barriers protecting underground mine entries in coal slurry impoundments is commonly conducted by assuming water and sometimes soil pressure on the end of a horizontal failure slice. However, a horizontal failure slice is not necessarily a critical surface and inclined surfaces need to be considered. To address this concern, a two-dimensional rigid body stability analysis is developed for earth barriers that accounts for normal and shear forces on the top and bottom of the failure slice, overburden loading on the failure slice, and normal and shear forces at the barrier-highwall interface. End forces on the failure slice include water pressure and K^sub o^ consolidated coal slurry. The minimum safety factor determined with the rigid body analysis shows reasonable agreement with finite element solutions using both mobilized shear stress and strength reduction techniques. The stability analysis demonstrates that previously assumed horizontal failure surfaces are not critical surfaces. Analysis of an example barrier subjected to increasing slurry depth and commensurate pore pressures shows the minimum safety factor increases slightly with increasing slurry depth. [PUBLICATION ABSTRACT]