Research About Blasting Vibration Speed Of Long Distance Little Space Tunnel

With the development of basic construction in traffic ,twin-line tunnels of little net distance and a new tunnel constructed between twin-line tunnels appear. A new tunnel betwwen twin-line tunnels in Jiaojinshan tunnel of Dalian city is studied in the thesis. A new tunnel is located between existing two paralleling tunnels,The tunnel is between two existed tunnels .The net distance is 5m and length along all line of tunnel is 1098m. The main difficulty in construction is that blasting in new tunnel is carried out under the condition ,which must ensure traffic of existed tunnels normally. If the standard of blasting vibration speed is 4～6cm/s, schedule of construction is slow.Hence aiming at characteristic of the tunnel , blasting parameters of test is made sure basing on theory analyse and correlative experience of engineering; and numerical simulation is put into practice with FEM soft;five tests is carried out ; safe and fast method of construction and blasting parameters are gained. In the end the new tunnel is constructed safely economicly and fast.