Numerical Simulation of Coal Pillar Loading With the Aid of a Strain- softening Finite Difference Model.
Proc 30th Symp on Rock Mech Morgantown West Virginia, 1989 :775-782
Numercial simulation of coal pillar loading has traditionally been a difficult task owing to the unique and highly variable properties of coal and the inability of numerical procedures to duplicate these properties. This U.S. Bureau of Mines simulation was based upon material properties developed from laboratory tests of coal cubes and examined against coal pillar strength data developed from actual underground measurements. The coal cube measurements indicated the coal followed a nonlinear mohr-coulomb failure criterion. The in situ measurements showed that a pillar yield zone developed similar to wilson's hypothesis; at high confinements, the pillar core seemed to follow a pseudo-ductile behavior. The strain-softening material model, based on a linear mohr-coulomb failure criterion, simulated coal cube and pillar behavior at moderate load conditions. However, at high loads the models were inaccurate, owing to an inadequate failure mechanism and/or to changes in the pillar constraints at the coalbed interface.
Proc. 30th Symp. on Rock Mech., Morgantown, West Virginia, 1989, PP. 775-782