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The influence of strain rate on indices of rock bump susceptibility |
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The influence of strain rate on indices of rock bump susceptibility Author: M. Bukowska
The indexes of rock susceptibility to bumps, which can be determined from uniaxial compression of rock samples in a stiff testing machine have been determined. Experiments have been carried out at kinematic control with longitudinal strain rate ranging between 10 sub -4 to 10 sub -1 s sub -1. The results have been obtained in the form of a complete stress-strain characteristic. On this basis indexes of rock susceptibility to bumbs have been defined. The stress, strain, stress-strain and energy indexes have been determined. Attention has been paid to the indexes defined from the pre-critical part of the stress-strain characteristic as well as the indexes defined from the pre- and post -critical parts of the characteristic. The influence of strain rate on the indexes of rock susceptibility to bumps for all kinds of Carboniferous rock occurring in the Upper Silesian Coal Basin has been analysed with respect to the whole population of rock samples. The obtained results have been referred to the bump prevention measures in two exstreme cases: a weak seam under a strong roof or a strong seam under a weak roof.
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2011