Deformation Control Technology For Shallow Buried Tunnel With Large Cross Section

With the development of the transportation network in our country,and the enlargement of the scale of highway and railway,the construction of railway tunnel and highway has been developed at top speed.Along with the "national freeway network planning" and "long-term railway network plan" adjustment have been promulgated,the construction of traffic network in China is more focused on the Western Loess Hilly region.This means that the cross phenomenon of the new engineering and construction in processing or existing projects will become increasingly common,and the difficulty will be greater.In this paper,based on the actual project,the deformation control of the large section shallow tunnel wear the highway is studied.Specific research contents are as follows:(1)Based on Zhongchuan tunnel under wear Tianchan highway as the engineering background,using the finite element numerical simulation analysis of the existing highway tunnel construction settlement.It is found that the surface subsidence rule of tunnel under orthogonal to wear is different from that of under oblique crossing.The settlement curve of each longitudinal section(driving direction)of the tunnel under the oblique crossing is almost the same.They are left and right translation relations.(2)The settlement law of shallow buried loess tunnel crossing highway is studied further.The influence of the formation cohesion and internal friction angle,the depth of the tunnel and the angle of tunnel on the road surface settlement are analyzed.The maximum settlement value and the width of the settlement trough will decrease with the increase of cohesion and internal friction angle respectively.In the shallow tunnel,the maximum settlement value and the width of the settlement trough are positively correlated with the depth of the tunnel.Through the tunnel under the angle the greater the settlement influence scope of the larger,the more uneven settlement trough bottom.Through the regression analysis of the surface settlement curve underdifferent oblique angles,the modified Peck formula can be used to predict the settlement of the inclined surface.(3)According to the actual Tianchan road condition and the modified Peck formula,Additional stress is analyzed of pavement structure.Then on the basis of highway related to the norms,to comprehensively consider the structural and functional requirements of highway,it puts forward the settlement control standard of the existing highway tunnel under oblique wear and classification.Finally,based on the settlement standards and the settlement results of pavement simulation in practical engineering.Zhanqiao as the emergency measures of Tianchan highway is recommended during the Zhongchuan tunnel construction.