In this study, bump potential in the vicinity of a fault zone associated with a longwall mining excavation is evaluated with respect to the different stages of shear strain in the normal fault through the use of a numerical modeling technique. The influence of stored and dissipated energy resulting from fault deformation and timing of longwall excavation on the potential for a bump adjacent to the fault was also investigated by the numerical model. While faults are commonly simulated as a single planar or nonplanar interface for a safety or stability analysis in underground mining excavation, the real 3D structure of a fault is often very complex with different branches that activate at different times. Furthermore, these branches are zones of nonzero thickness where material continuously undergoes damage even during interseismic periods. The FLAC3D model successfully demonstrates and creates the 3D fault zone as a normal type structure in the entire thickness of the model. The normal fault structure and its displacement result in the induced deformation in the model. Several panels of a longwall excavation are virtually placed and excavated adjacent to the fault. The characteristics of stored and dissipated energy associated with the panel excavations are examined and observed at the different stages of shear strain in the fault to evaluate bump potential. Depending on the shear strain in the fault, the energy characteristics adjacent to the longwall panels present different degrees of bump potential, which is not possible to capture by conventional fault simulation using an interface.
Development of a 3D Numerical Tool for Assessing the Mechanical Impact of a Fault-Rupture by Normal Fault on Underground Excavations
Kim, B. H., and M. K. Larson. "Development of a 3D Numerical Tool for Assessing the Mechanical Impact of a Fault-Rupture by Normal Fault on Underground Excavations." Paper presented at the 53rd U.S. Rock Mechanics/Geomechanics Symposium, New York City, New York, June 2019.
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