Research Of Mechanical Characteristics Of Tunnel Advance Support And Software Development

China is a mountainous country.During the construction of mountain tunnels,some auxiliary measures must be taken to pre-support or pre-reinforcement the stratum because the tunnel face can not be self-stabilized or the surface settlement is too large.leading conduit and pipe roof are widely used pre support measures.Based on the Badong Tunnel,the mechanical mechanism of leading conduit and pipe roof and the stability of tunnel face under supporting conditions are studied in this paper.Through theoretical derivation,numerical simulation and software development,some research results which can be used in engineering practice are obtained.The main contents of the thesis are as follows:(1)The supporting mechanism of leading conduit and pipe roofis analyzed,the determination method of tunnel surrounding rock pressure and the theory of surrounding rock pressure are briefly described,According to Winkler elastic foundation beam theory and Pasternak elastic foundation beam theory,Winkler foundation model and Pasternak foundation model of leading conduit and pipe roof are established.The deflection,subgrade reaction,angle,bending moment and shear force at any point of small pipe and pipe roof can be obtained by deriving the deflection equation,subgrade reaction equation,angleequation,bending moment and shear force equation.Based on Winkler foundation model and Pasternak foundation model,the mechanical analysis of leading conduit and pipe roof is carried out with Badong tunnel as an example.Based on the Winkler foundation model,the effects of different factors on the Pipe roof deflection and the stability of the tunnel face are analyzed.(2)The calculation software of tunnel advance support is developed,which can be used to calculate the surrounding rock pressure of deep and shallow buried tunnel and the coefficient matrix of Winkler foundation model and Pasternak foundation model.It is also convenient to store,query,modify and delete the data.(3)ABAQUS finite element software is used for numerical analysis,the influence of different supporting conditions and different reinforcement thickness and different tunnel buried depth on the reinforcement effect is compared and analyzed,and the effect of small pipe length and circumferential spacing and longitudinal spacing and extrapolation angle on reinforcement effect is also analyzed.