Study On The Influence Of The Staggered Segment Of Shield Tunnel On The Mechanical Properties Of Tunnel

At present,tunnels constructed by the shield method use prefabricated lining segments as the main supporting structure,and the segments are connected by bolts to form an integral tunnel structure.In the shield construction process,due to factors such as stratum geology,construction process control,and tunnel settlement,the misalignment of lining segments is a common quality problem in shield tunnels at present.Problems such as segment cracking,chipping,and water leakage caused by the misalignment of lining segments directly affect the quality of the project and subsequent operation and maintenance.Based on an underground comprehensive pipe gallery project,this paper investigates the misalignment of lining segments produced on site,analyzes its causes,and analyzes the effect of misalignment of lining segments on the mechanical properties of the tunnel through theoretical analysis and numerical simulation.The main contents are as follows:1.Using the finite element software Abaqus to establish a three-dimensional finite element analysis software,taking shield subway tunnels and shield comprehensive pipe corridors as objects,study the effect of the amount of lining segment misalignment on the bending performance of the lining segment joints of the shield tunnel and the lining pipe The influence of the internal force of the film.Under pure bending conditions,the variation law of segment joint bending resistance and tunnel mechanical characteristics under different lining segment misalignment were obtained,and the law of local stress concentration and local displacement caused by lining segment misalignment was proved.2.Analyzed the changes in the mechanical properties of ordinary shield tunnel lining segments under different strata resistance,buried depth and groundwater level conditions under different displacement conditions,and the location of local damage to the tunnel under the displacement amount,and the tunnel’s weakness Wait.3.Analyzed the changes in the mechanical properties of the lining segment under the combined action of the underground composite tunnel shield tunnel structure and the secondary lining under complex conditions and different displacements and the deformation characteristics of the tunnel,and compared the changes in the mechanical properties of ordinary subway tunnels.It is proposed that the requirements for the amount of misalignment in a tunnel with a secondary lining structure should be more stringent,which can provide a reference for the design and later operation and maintenance of the tunnel.