Study on effect of tunnelling blasting on existing adjacent tunnel

Based on the actual tunnel excavation projects, a three‐dimensional finite element model of tunnel excavation is set up, and the particle vibrations and stress distributions are analysed at the existing adjacent tunnel concrete linings. The results of calculation show that in the whole range of investigation, the vertical peak particle vibrations are bigger than those in the other two directions, but the main tensile stresses in the tunnel vault crown and bottom are in the horizontal direction, which prove that the vertical peak particle vibrations cannot totally represent the stress states of rocks. In actual projects, the blasting peak particle vibrations should be controlled, and the stress states of rocks should be analysed as well. During our actual tunnel excavation, the maximum peak particle vibration calculated is 0·0494 m s–1, which is lower than the 0·05 m s–1 required in projects; and the maximum tensile stress in the tunnel vault crown is 0·54 MPa. That is to say, the tunnel concrete linings are not affected.