The Effect Of Blasting Vibration In Continuous-double-arch Tunnel

The design and construction of tunnel have meet new challenges because of the appearance of the new type continuous-double-arch tunnel. The new type tunnel has larger cross-area, special structural and different excavating way. The technique of driving blasting is used as a main constructive way in tunnels in rocky zone at present. By this way,blasting vibration effect is inevitable. The blasting vibration effect is concerned with not only the stability of the surrounding rock and tunnel structural but also the safety of buildings around the tunnel. The effect of special structural and excavating way to the blasting vibration should be taken into account and be studied. In view of the Dong-kou-tang continuous-double-arch tunnel in Shao-Huai highway in Hunan Province,the field experiments on blasting vibration effect have been done. By measuring the particle vibration velocity in the surface-ground and the central wall of the tunnel,the characters of the blasting seismic waves have been studied. Combing the engineering example, the blasting vibration is calculated by using the dynamic FEM calculation program. In this paper, three type of surrounding rocks are taken into account, the results indicate that the young's modulus plays an important role in the blasting vibration question in the tunnel. And the effect of the different diving sequence of the left and right hole is also considered. According to the results, we can know that it is much more safety to construct the left hole first. And in this paper, it also studied the importance of the delay interval in the blasting vibration effect. At last, the particle vibration velocity calculated is validated by the one measured in the Dong-kou-tang continuous-double-arch tunnel.