Abstract:On the basis of the theory that quasistatic pressure resulted from the detonation generated gases plays a major role in the mechanism of rock presplitting, Fast Lagrangian Analysis of Continua (FLAC) was employed to predict the appropriate quasistatic pressure for generating a presplit in a presplit blast under a given set of conditions and investigate the influence of detonation sequences on the predicted pressure. The simulation results showed that when the quasistatic pressure in each blast-hole was appropriate, tensile failure would occur along the line connecting the centres of the blast-holes and a presplit would be formed, and that the detonation sequences did not have significant influence on the appropriate quasistatic pressure. In order to obtain this pressure, a formula was derived to estimate the amount of explosive for each blast-hole. Furthermore, field experiments were carried out, and the test results demonstrated that they are consistent with the numerical simulation results and the numerical simulation method, therefore, is very effective in modeling rock presplitting, and that the suggested formula could be used to estimate the amount of explosive for each blasthole on the predicted quasistatic pressure.

Key words: FLAC　numerical simulation　rock presplitting