MULSIM/NL theoretical and programmer's manual.
Denver, CO: U.S. Department of the Interior, Bureau of Mines, IC 9321, 1992 Jan; :1-52
MULSIM/NL (multiple seams, nonlinear) is a three-dimensional boundary-element method (BEM) program developed at the U.S. Bureau of Mines for stress and displacement analysis of coal mines and thin metalliferous veins. It can analyze one to four parallel seams that can have any orientation with respect to the earth's surface. Three main new features distinguish MULSIM/NL rom its predecessors: (1) nonlinear material models, (2) multiple mining steps, and (3) energy release and strain energy computations. MULSIM/NL has six material models for the in-seam material: (1) linear elastic for coal, (2) strain softening, (3) elastic plastic, (4) bilinear hardening, (5) strain hardening, and (6) linear elastic for gob. Detailed checks show that numerical stress and displacement calculations compare well to known analytic solutions for simple problems. The total energy release calculated by mulsim/nl is comprised of three basic terms: (1) strain energy release from the mined-out material, (2) linear kinetic energy release due to change in gravitational potential over the mined-out area, and (3) nonlinear kinetic energy release due to nonlinear materials in the total backfill and gob area. The strain energy release term is modified to account for nonlinear stress-strain behavior in the unmined materials. Comparisons of these numerical energy release rate calculations with known analytic solutions show excellent agreement.
Mining-industry; Coal-mining; Geology; Computer-models; Computer-software; Room-and-pillar-mining
NIOSH, Pittsburgh Research Laboratory, P.O. Box 18070, Pittsburgh, PA 15236
IH; Information Circular
NTIS Accession No.
Denver, CO: U.S. Department of the Interior, Bureau of Mines, IC 9321