Numerical Simulation And Dynamic Characteristics Of Tunnel Excavation With Small Clear Distance

In recent years,our country's economic rapid development is accompanied by the development of the transportation sector.Our country pays more and more attention to the construction of infrastructure,and has invested a lot of money in the construction of roads,bridges and tunnels.As a important part of the traffic artery in China,tunnel construction also has received considerable attention.It is fast and convenient,can save time cost,and its environmental damage is small.So the tunnel plays an increasingly important role.With the rapid development of the highway in mountainous area,small clear distance tunnel had become a major form of mountain tunnel structure,because of the small clear distance,tunnel lining and surrounding rock stress distribution is more complex,so it is necessary to do research in small clear distance tunnel from the perspectives of design and construction.This paper,depends on the ZhongXing tunnel's engineering geology.The rock class is ?,? respectively,belonging to the soft surrounding rock.According to relevant data and information provide by engineering,theoretical research and investigation and related calculation has been done,concrete results are as follows:(1)During the excavation of the upper part of the tunnel,the deformation increased significantly,after supporting function,can control the deformation.In different rock conditions,select the appropriate method is an effective means to control the deformation and stress of initial supporting.(2)For small spacing tunnel,the construction of the tunnel under the condition of a certain net distance is satisfied,and the influence of the support stress and anchor bolt axial force is small.The bias effect produced by the construction of the rear tunnel has a significant effect on the two lining,The first two hole lining effective control and tunnel face spacing can reduce the impact of the two lining structure of the first hole.(3)In the existing blasting parameters,after the hole blasting on the first hole has an impact,but the indicators are within the norms of the safety range,the existing blasting excavation will not affect the safety and stability of the tunnel structure.