Abstract:

The degree on fragmentated rock is one of all technical and economic indicators of the synthetic drilling and blasting. This issue was very interested in the drilling blasting on opencast site, however, very little research on it in tunnel drilling blasting. On the other hand, the evaluation of economic efficiency of the drilling explosion in the tunnel is not a comprehensive review of the extent of the impact degree of smashing of rock and soil after explosion them on the economic efficiency of the whole chain: drilling - explosion - loading - transport. Hence, this paper presents the results of empirical research, analysis, evaluation and compared the degree on fragmentated rock based on electrical explosion model between two cases explosion: one free surface and two free surface. The empirical analysis allows evaluation law of fragmentated rock which depending on the specific energy to destroy a unit volume of rock, which lead to obtain the coefficient affecting of number of the free surface, as a basis for explosion theory to apply to the underground