Details:

Personal Author:
Zipf, R. Karl, Jr. ; Heuze, Francois E.
Zipf, R. Karl, Jr. ; Heuze, Francois E. Less -
Corporate Authors:
Pittsburgh Research Laboratory (National Institute for Occupational Safety and Health)
Conference Authors:
International Conference on Ground Control in Mining (22nd : 2003 August 5-7 : Morgantown, WV)
Description:
Stress analysis programs such as MULSIM/NL, LAMODEL, MinSim 2000, and EXAMINETAB are used in the mining industry to analyze stresses and displacements in coal mines, platinum mines, gold reefs, and tabular-type deposits. These relatively simple numerical models can efficiently simulate yielding and failure of a rock mass near a mine opening and subsequent stress transfer. The main input parameters for these models are a family of nonlinear stress-strain curves for the in-seam material. For many applications of these models, such as in coal mining, extensive field measurements and observations exist from which to estimate these stress-strain curves and calibrate the numerical models; however, such measurements are lacking for other types of mines. A three-step method is presented to determine nonlinear stress-strain curves for boundary-element (BE) programs used in many mining applications. The method requires a suite of laboratory-scale strength tests at various confining pressures. Note that this analysis uses laboratory-measured strength and modulus properties of alluvium. The dependency of the mechanical properties of alluvium on scale has not been established, although more tests are being planned. However, it is believed that the relative comparisons performed are valuable regardless of scale effects. First, the FLAC2D computer program is used to model the laboratory tests and determine cohesion (c) and friction angle () for a Mohr-Coulomb material model. Second, another FLAC2D model uses the c and values to calculate vertical stress and strain around a single opening in the rock mass. This model calculates the stress-strain path of points at various distances from the opening boundary. Finally, based on these stress-strain paths, the stress-strain curves needed for a BE analysis are derived. This three-step method was demonstrated in a large, flat-lying underground test facility in very weak rock. The BE analyses agreed well with observations of failure at the test facility and provided a basis for evaluating the behavior of alternative layouts.
Subject:
[+]
Mining

Source:
Proceedings of the 22nd International Conference on Ground Control in Mining, August 5-7, 2003, Morgantown, West Virginia. Peng SS, Mark C, Khair AW, Heasley KA, eds., Morgantown, WV: West Virginia University, 2003 Aug; :308-317
Document Type:
Book Chapter
Genre:
Conference Publications
Collection(s):
National Institute for Occupational Safety and Health
Main Document Checksum:
[+]
urn:sha256:a423e0bd8252d0f9f2d2322dcf63b11b92322c0a1f097438f6df24447b52c017
File Type:

Supporting Files

• No Additional Files

More +