Monitoring and simulation of mining-induced subsidence

To quantify the influence which rock discontinuities have on mining-induced subsidence, extensive deformation measurements were made during excavation of a longwall panel and, a two-dimensional rigid block computer model was utilized to simulate rock mass conditions and displacements. The jointed rock block mesh was developed from stratigraphie and joint set data while rigid block contact stiffnesses were estimated from intact rock properties. The rigid block model was capable of simulating the distribution of vertical displacements within the overburden, but it could not simulate intense fracturing in strata above the zone of block caving which was inferred by the inclinometer data. The best agreement between simulated and measured displacements was obtained for the simulated case in which a relatively low stiffness value was maintained constant for all rigid block contacts.