NUMERICAL-SIMULATION OF CAVED GOAF BEHAVIOR IN LONGWALL WORKINGS

Modifications of the Chamber of Mines formula, which defines stress-strain behaviour of fills, were attempted to suit caved goaf material behaviour. The constants of this formula were varied to run 2-D displacement discontinuity type boundary element models. This variation was carried out by trial and error to improve the stress distribution over the goaf as per available field experience. It was seen that the constants in the formula must be varied across the goaf in order to obtain realistic normal stress distributions. Final values of these constants are recommended for different cover depths and seam thicknesses.