铁路隧道铺底混凝土顶面纵向裂纹扩展研究OA

In order to study the crack propagation behavior of longitudinal cracks on the top surface of tunnel bottom concrete,fracture mechanics theory and the finite element software ABAQUS were applied to numerical-ly simulate the propagation of longitudinal cracks at three locations:the tunnel bottom structure center,track,and tie end.The study analyzes the stress intensity factors(K-values)and propagation paths of these longitudi-nal cracks in the context of the surrounding rock pressure and the coupled effect of train dynamic loads.The re-sults show that dynamic loads from the train significantly promote the propagation of longitudinal cracks,with a more notable effect on KⅡ.When the crack depth at the center,track and tie end is 180,140 and 100 mm,re-spectively,the crack tip KⅠ at the three positions reaches the maximum value.As the crack depth increases,the influence on the crack tip KⅡ gradually increases,particularly on the tie end KⅡ.During the crack propaga-tion process,the initial stage is mainly dominated by KⅠ,while the later stage is mainly governed by KⅡ.The maximum crack propagation depth at all three locations is 0.8 meters.The research findings provide theoretical guidance and references for tunnel design and crack remediation.