Numerical and field analysis of single-hole blasting mechanism in conglomerate rock mass of Gotvand Olya Dam

Several relations are presented in order to specify blasting dynamic loading associated with analytical, field and experimental analysis. Dynamic loading type, maximum pressure and consequent duration time can affect the numerical simulation results of fragmentations, damage zone and maximum radial crack length in the vicinity of the blast hole and ground vibrations. These in turn depend on the maximum explosion pressure, applied loading time and the type of explosion function (pressure versus time) which determine the area under the pressure-time curve. In this article, different common correlations for dynamic loading of explosions are simulated using UDEC numerical discrete element software and the results are compared with field studies obtained from PETN explosions used in the conglomerate rockmass in Gotvand Olya dam. Considering the mutual explosive and rockmass characteristics, the maximum applied pressure to the blast hole was found to be 4.59GPa based on both Liu and Tidman semi-empirical relationship and Gamma constant law. Results of numerical and field studies suggest that Yon and Jeon relation coincide with the field study data, considering the 1.0m radial crack length, ground vibrations recorded during the field tests at 5m and 12m distances from the blast hole are 42.36 and 7.91 mm/s, respectively.