Study On The Deformation And Damage Mechanisms Of Shield Tunnel Athawart Ground Fissure With 30°

On the background of Xi'an Metro #1 line engineering, the large proportion (1:5) segment lining structure physical modeling experiment of shield tunnel athwart the ground fissure with 30°was designed according to the similarity theory. To understand the pattern and characteristics of the deformation and damage of shield tunnel. The results show:(1) The main deformation and damage of structural are shear stress, with some local torsional deformations,the structure has the trends of overall bending when the beginning of settlement.(2) To vertical displacement of ground fissures in the 20cm range, the main deformation and damage of segment lining structure range from ring 14 to ring 19. The deformation and damage of the ring 13 (the hanging side) and ring 20 (the lying side) is less destroy, and other lining segments show little deformation. Based on the external diameter of D=1.2m, we calculated that lining deformation is equivalent to 1.25D for the hanging side and 0.75D for the lying side.(3) The deformation and damage of segment ring is asymmetric and partial compressive.(4) With the increase in the movements of ground fissure, the dislocation of the segment lining structure is higher. Therefore, we conclude that the segment lining structure of shield tunnel is unsuitable to the places where ground fissures are very active.The numerical simulation of the physical model test is carried out used ANSYS finite element software. The change rule of displacement, stress, strain, etc, based the numerical simulation is consistent with that of model test.This research has enriched the theory about the deformation and damage mechanisms of segment lining structure of shield tunnel passing through the the geological environment of ground fissures, which can be provided as the reference to structure design of metro tunnel.