Shigen-to-sozai, Vol.116, No.7, pp.617-622.
Experiment Study for Flying Characteristics and Control of Fly Rock Caused by Blasting
Yuji OGATA1, Yuji WADA2, Masahiro SETO1 and Kunihisa KATSUYAMA1
| 1. National Institute for Resources and Environment,
AIST, MITI, Tsukuba 305-8569 2. Faculty of Engineering, The University of Tokyo |
| Blasting to break the rock and structure
using energy of explosive is one of the important
operation for civil and mining engineering.
In this research some test blasting using
high-speed camera, high-speed video and pr?cis
blasting system were carried out to study
the generation mechanism of fly rock caused
by blasting. Seven full scale test blasts
in the quarry with different quantities of
explosives and burden were carried out to
study the flying characteristics of fly rock
caused by blasting. DDA (Discontinuous Deformation
Analysis) was applied for numerical simulation
of full scale blasting. The results are briefly
summarized as follows; 1. Initial fracture in the model experiment using the glass material was caused by the Hopkinson effect. The separated fragment, considered as a fly rock, then is accelerated in the direction of a free face by the remained stress. 2. The flight distance of fly rock generated near the minimum resistance line have longer compared with other fly rock in the mortar block experiment. The reason is considered that fly rock near the minimum resistance line was influenced easily by the impact stress and the expansion gas generated by the detonator and detonating fuse. Moreover, it was shown to be able to control the flight distance of the fly rock by applying the precise initiation method. 3. The generation situation and the flying characteristics of the fly rock generated in the bench blasting were clarified from full scale test blasting. Moreover, it was shown that DDA was able to apply for the numeric simulation of bench blasting. |
| KEY WORDS: Fly Rock, Hopkinson Effect, Control Blasting, DDA |