航程(航空)
岩石爆破
地质学
工程类
岩土工程
航空航天工程
标识
DOI:10.1016/j.ijrmms.2022.105204
摘要
A sufficient database of measured flyrock ranges produced by blasting at a particular site can be used to determine the probability that flyrock will exceed any prescribed range. Such a probabilistic analysis is given for data from 6 sites (surface mines and quarries). A flyrock model based on two-dimensional (2D) ballistics, incorporating the site-specific blast designs, is also used to predict a set of flyrock ranges for each site. It is shown that the exceedence probabilities of the modelled ranges are consistent with those determined for the measured ranges. The model uses flyrock fragments having a random launch angle and size; it also uses various fragment shapes whose lift and drag forces in flight are based on wind tunnel experiments. Mines often face a problem of setting rational exclusion zones for flyrock generated at different working levels due to impact with pit walls. Thus a pseudo-3D version of the model was constructed in which the radial direction was continually rotated to span the 3D space of a pit surface. This model showed a significant restriction in flyrock range due to pit walls; it also showed a strong influence due to the shape of the flyrock fragments, suggesting a possible mechanism for wild flyrock. A fully 3D model was also constructed for spherical fragments, and showed that the influence of a prevailing wind as well as surface topography is not inconsequential to flyrock risk assessment. The 3D model has application for the protection of Heritage Sites from flyrock impact.
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