Study On The Influence Of Tunnel Blasting For Surrounding Rock's Stability

The technique of driving blasting is used as a main constructive way in shallow tunnels in rocky zone. By this way, blasting seismic effect is inevitable. Blasting vibration has effect on the surrounding rock. When the blasting vibration velocity is greater than the critical velocity, rock will be destroyed, and the stability of the surrounding rock losts. This paper study on the influence of blasting for surrounding rock's stability by the means of field test and software simulation under the project of Qipanshan lion. The main achievements as follows:Firstly, we conducted three experiments at the scene. The first one is vibration test in far zone of the tunnel blasting; the second one is vibration test with full-face of the tunnel; the third is vibration test in near zone of the tunnel blasting. We use test data to make regression analysis,and get the empirical formulas for blasting vibration under the law of vibration velocity attenuation.Secondly, we simulate the blasting by software LS-DYNA, obtain the vibration velocity of every particle under three levels surrounding rock's blasting. After that, we modified some empirical formulas for blasting.Thirdly, we carried out mechanical analysis from the two sides:the whole rock and the structural plane of rock. We calculate the critical velocity of the Qipanshan tunnel under blasting. Then we worked out the rock tunnel critical velocity table.