عنوان مقاله [English]
Despite many improvement in the underground construction by mechanized methods and the whole section, the drilling and blasting still plays an important role in the construction of tunnels and mines. In addition to various advantages such as flexibility and low capital cost, this method also has disadvantages, one of which is the expansion of the blast damage zone around the underground structure, which leads to increased joints and cracks in the surrounding environment and consequently reduced resistance and increased permeability also In some cases land subsidence occurs . Various factors affect the damage zone. Various methods such as measurement, experimental and modeling methods are available to investigate these factors. In this paper, numerical modeling has been done for three different state of drilling a. In addition to a brief mention of different factors affecting the damage zone, it is determined that the maximum impact on the damage area is related to tensile strength and cohesion of rock. In addition, the effect of rock geological strength index (GSI) has been investigated as one of the important factors in recognizing rock mass and the effect of reducing the damage area with increasing GSI has been observed.