Drilling and blasting has always been the main construction method for rock excavation of underground and surface buildings. This way has strong adaptability to rock geological conditions and low excavation cost, and is particularly suitable for cavern construction with hard rock. 

When excavating underground buildings by drilling and blasting, blasting design should be made according to design requirements, geological conditions, blasting materials and drilling equipment.

The main tasks of drilling and blasting design are: 

① Determine the arrangement of blast-holes in the excavation section, including the location, depth and direction of various blast-holes; 

② Determine the charge, charge structure and plugging method of various blast-holes; 

③ Determine the detonation method and detonation sequence of various blast-holes.

Compared with open-pit excavation blasting, underground cavern rock excavation and blasting construction has the following main characteristics:

(1) Due to the influence of lighting, ventilation, noise and water seepage, the drilling and blasting working conditions are poor; the drilling and blasting work is carried out in conjunction with support, slag transportation and other processes, which limits the construction site and increases the difficulty of construction.

(2) There are few free blasting surfaces, and the clamping effect of rocks is large, which increases the difficulty of breaking rocks and increases the unit consumption of rock blasting.

(3) High blasting quality requirements. Generally, strict standards are set for the formation of the profile of the cave section, and over-excavation is controlled and under-excavation is not allowed. It is necessary to prevent flying rocks and air shock waves from damaging the relevant facilities and structures in the cave. The disturbance and quality impact of blasting on the surrounding rock and nearby supporting structures should be controlled as much as possible to ensure the safety and stability of the cave.