Research on Mechanism of Lining Cracking in Single-track Railway Tunnels Influenced by Cavity within Arches Region
In order to study the stress characteristics and crack mechanism of the lining structure in the concealed cavity region,which proposes an extended finite element refined simulation method that accurately reflects the influence of lining cavity.To verify the reinforcement method of reinforced rib jointed anchor net unit.By utilizing a non-destructive testing method based on ground penetrating radar,the geometric dimensions of cavities behind the tunnel walls are accurately determined,which is based on an actual engineering project of a damaged lining railway tunnel in service.A numerical simulation mesh model is established using extended finite element to accurately represent the influence of cavities and reveal the mechanism of lining cracking.Based on numerical analysis and on-site monitoring,verify the reinforcement method of reinforced rib anchor mesh spray reinforcement.The results shows that non-destructive testing reveal the presence of severe cavity behind the arch walls of the tunnel,primarily in the arch area above the arch spring line,with an average depth ranging from 0.17m to 0.93m.The numerical simulation results demonstrate that in the presence of cavities behind the lining arch,the cavity azimuth angle has a greater impact on the lining stress compared to the void radial depth.When the cavity azimuth angle is small,the lining is less susceptible to damage or the occurrence of tensile cracks on the outer surface accompanied by internal surface crushing.With the continuous increase of the cavity angle,tensile cracks are more likely to occur on the inner surface of the lining,and the cracking position moves downwards.Reinforced rib jointed anchor net unit can significantly enhance the stiffness of the reinforcement area and improve the structural load-bearing performance.The conclusions show that the azimuth angle of cavities behind the lining has a significant influence on the stress state of the structure.The proposed numerical analysis method can effectively reflect the mechanism of lining cracking in cavity-tunnel arches and accurately characterize the morphology of the cracks,the reinforcement method of using reinforced ribs with anchor mesh is effective.
concealed cavitynon-destructive testingextended finite elementlining crackreinforced rib jointed anchor net unit
万方数据
维普
