Research on the mechanism and application of wedge-straightcomposite trench blasting in rock roadway

The key to the speed of rock roadway excavation lies in trenching. This paper aims at the problems of relatively single trenching technology and low blasting efficiency existing in the rock roadway drilling and blasting method, and conducts an experimental study on the physical model of rock roadway wedge-straight composite trenching blasting. Through model tests, the characteristics of the trench cavity under different trench blasting forms are compared and analyzed. Meanwhile, high-speed photography technology is used to observe and analyze the throwing process of the trench rock mass. The results show that the trench depth after wedge-straight composite trench blasting is 27% longer than that after wedge-straight trench blasting, the trench cavity diameter is 16% longer, and the trench cavity volume is 28% larger. The proportion of large-sized crushed stones in wedge-straight trench blasting is 24.6%, and the proportion of the remaining crushed stones is 7.4%. The proportion of large-sized crushed stones in wedge-straight composite trench blasting is 8.1%, and the proportion of the remaining crushed stones is 91.9%. Wedge-straight composite trench blasting has a significant effect on reducing large-sized gangue. It is concluded that in the case of a smaller cross-section and higher rock strength, the wedge-straight composite trench blasting method can better achieve the effect of rock breaking and cavity expansion, thereby improving the utilization rate of the blast holes.