Initiation of Tectonic Earthquakes during Underground Mining
G. G. Kocharyan, A. M. Budkov, S. B. Kishkina
Institute of Geosphere Dynamics, Russian Academy of Sciences, Moscow, 119334 Russia
Keywords: индуцированная сейсмичность, техногенные землетрясения, горные выработки, мониторинг, эффективная жесткость массива, разломные зоны, кулоновское напряжение, моделирование, Induced seismicity, induced earthquakes, underground openings, monitoring, actual rock mass stiffness, faulting zones, Coulomb stress, modeling
Abstract
The influence of underground excavations arranged nearby faults on the initiation of large seismic event is considered. Numerical modeling proves that amount of underground openings affects actual stiffness of rocks and initiates dynamic movements accompanied by intensive seismic radiation. As the rock mass quality worsens, the effective shear modulus drops. The calculations show that the effective shear modulus lowers by 20% for the stope on the same horizon, decreases 1.5 times in case of the stopes arranged on two horizons and nearly halves for three horizons. Such reduction in the actual shear stiffness of rock mass may be critical in terms of initiation of dynamic shift along a fault.
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