Highway Tunnel Excavation Caused By The Settlement Prediction And Influence Factors Of The Existing Highway

With the rapid development of transport a large number of tunnels beneath the existing roads has appeared, It is necessary to forecast the subsidence of ground surface which caused by tunnel excavation for protecting the normal operation of road and maintaining the salty of tunnel construction.Based on Hong zhushan tunnel beneath the existing road, this thesis analyses the surface subsidence and deformation caused by the construction of tunnel with the methods of Peck formula, random medium theory and numerical simulation.This thesis includes work as follows:1.The ground subsidence and deformation caused by the construction of double parallel tunnels is obtained by the Peck formula with overlay superposition method.The method,which is used to caculated the surfacesubsidence and deformation caused by the construction of double parallel tunnels,js proved to be appropriate through examples.2. Applying of double integral substitution method transform from cartesian coordinates' stochastic medium theory to polar coordinates',which can calculate the surface subsidence and deformation caused by the construction of arbitrary shape of tunnel. Peck formula and random medium theory are similar,which make the calculation parameters of random medium theory can be expressed by the calculation parameters of Peck formula.This improved stochastic medium theory is more suitable for engineering practice, This thesis make use of the improved random medium theory to calculate the surface subsidence caused by the construction of double parallel tunnels, which is proved to be appropriate through examples.3.Applying of FLAC3D finite difference software forecast the surface subsidence caused by the construction of Hong zhushan double parallel tunnels,which is compared with the subsidence that is calculated respectively by the uses of Peck formula and radom mediun theory.3.Applying of FLAC3D finite difference software studies the different impact factors of the surface subsidence of the shallow tunnel,which focuses on the nature of rock, the tunnel depth, the construction method,the excavation of footage,the supporting measures and the load of surface.4.The types and reasons of road broken which cuased by the construction of tunnel has been summed up through the observation of construction of Hong zhushan double parallel tunnels,and the measures which control road surface subsidence has been proposed.The formula of road surface subsidence standard has been deduced.