Numerical Simulation Of Mechanical Response Of Deep Buried Composite Lining Tunnel

With the advancement of urbanization and transportation development in China,there is an increasing demand for deep buried tunnel construction.Composite lining is a commonly used deep buried tunnel structure,and the mechanical response of tunnel lining under deep burial conditions is a key issue for design and construction consideration.In this thesis,firstly,the analytical solution of the mechanics of doublelayered cylindrical structure under axisymmetric loading is given based on the elasticity,and the numerical simulation of circular tunnel lining section is carried out based on the load structure method and the stratigraphic structure method using the finite element software ANSYS to verify the accuracy of the numerical simulation method.Secondly,numerical simulation of the internal forces and deformation of the double-line composite lined tunnel was carried out based on the load structure method by using the finite element software ANSYS,and it can be seen that the maximum values of axial forces and bending moments of the secondary lining are obtained at the foot of the arch,and the deformation is mainly concentrated at the bottom of the arch.Finally,the stresses and displacements of the composite lining of the single-line and double-line tunnel were numerically simulated by the finite element software ANSYS,considering the two cases of smooth contact and complete contact between the linings,and the effects of lateral pressure coefficient,lining thickness and uniform internal water pressure on the lining stresses and displacements were discussed under the case of smooth contact.The results show that the Mises stress maximum in the secondary lining of the double-line tunnel increases with the increase of lateral pressure coefficient and secondary lining thickness,and decreases with the increase of initial support thickness.The maximum Mises stress in the secondary lining of single-line tunnel decreases with the increase of lateral pressure coefficient and then increases with the increase of lining thickness.Both decrease and then increase with the increase of the uniform internal water pressure.The maximum Mises stresses of the secondary lining of a double-line tunnel are greater than those of a single-line tunnel under the same conditions,except for the higher mean internal water pressure.The settlement of the vault of the secondary lining of single-line and double-line tunnel decreases with the increase of lateral pressure coefficient and lining thickness,and the settlement of the vault of the secondary lining of single-line and double-line tunnel increases and decreases respectively with the increase of the mean internal water pressure.In the same case,the vault settlement of the secondary lining of the double-line tunnel is larger than that of the single-line tunnel.