Research On The Impacts Of Explosion Excavation Of Following Hole On Initial Support Of Small-distance Tunnel

It is no doubt that in the field of transportation, the construction of First-Class highway becomes dominate industry, and also plays a very important role in improving the quality of people’s living. The tunnel is the controlled project of the highway. Due to the topographic reason and the complication of the geologic structure, there are lots of constraints which made the distance of the neighborhood tunnel could not be controlled within the range in the construction of mountain First-Class highway. Therefore, So the small clear distance tunnel arises at the historic moment.Small clear distance tunnel in the wave of blasting excavation would produce energy wave, which produced by the explosion would cause gigantic vibration near the explosion points. In the construction of small distance tunnel, it is necessary to design the explosion and monitor the vibration of explosion to ensure the security of construction.Based on Chongqing Shuangbei Tunnel, this article analyzed the monitoring database of tunnel explosion vibration first, then used the transience finite analysis software MIDAS\GTS to establish the numerical simulation model of Shuangbei Tunnel, researched the response regularity of primary supporting structural dynamics in the existing hole of the tunnel under the different working condition while exploding the following hole.These following are the specific questions:①Mainly researched the transformation regularity of the primary supporting in the existing hole under different buried depth and the vibration regularity of each key point while exploding the following hole.②Mainly researched the speed and displacement of the primary supporting in the existing hole under different supporting pattern while exploding the following hole.③Mainly researched the influence of the primary supporting in the existing hole while exploding the following hole under different longitudinal distance of the working face, the relationship of the reasonable longitudinal distance between the excavation widths of the tunnel which could provide certain guidance of the explosion design in the same type of tunnel.④Mainly researched the influence of the primary supporting in the existing hole while exploding the following hole under different surrounding rock classification, and the transformation regularity of the primary supporting in the existing hole under different longitudinal distance.