Experiment On The Blocking Mechanism Of Tunnel Blasting Hole

Stemming is a necessary procedure in the construction of the tunnel blasting,and has a direct and significant influence on the blasting effect. Non-clogging or plugging with poor quality will lead to the explosion gas rush out of hole prematurely. So as to effect the role of rock-breaking functioning adequately, and will produce large amounts of toxic gases, which poses a health risk to workers.First, the detriment of non-clogging hole is expounded briefly, such as blasting slungshot,chunks of rock, high concentration dust during the tunnel excavation.Then, the roles of shock waves, stress waves and detonation gas have played in the process of the rock blasting is analyzed according to the rock blasting mechanism. In the meantime, it's explained that why the blast hole stemming can improve the blasting effect greatly by using the mechanics theory. Next, analyze the stemming movement law in the hole by a motion model, and study the differences between the two subjects comparatively.After analyzing the conventional plug blasting, the advantages of water pressure blasting is analyzed by comparing the explosion pressure, the hole wall of initial pressure, and detonation gas quasi-static stress field, in order to determine the optimal charging structure. Subsequently, it's proved that blast-hole stemming is necessary and the hydraulic blasting technology is predominan, through the field test of two engineering examplest. The theory and experience in the paper can be used for reference to other tunnel blasting engineering.