Presplit blasting mainly affects the upper part of rock mass.
2
目前,在光面爆破设计与施工中,均未考虑主爆孔先爆造成光爆层岩石损伤对光面爆破参数的影响。
At present, in the design and construction of smooth blasting, considering few influence that main blast hole 'first blast damage to rock of smooth blasting parameters.
When we dig a tunnel in sericite quartz-schist with dobby drills, regular bending of the boreholes appears, which affects drilling speed and the borehole quality.