Air-tightness Test and Mechanical Model of Gasket at Segment Joint of Low Vacuum Tunnel
Given the segment lining structure as a reasonable solution to build a low vacuum operating environment for trains,the air-tightness at its joints is one of the key issues to be addressed.Aiming at solving such problems,an experi-mental apparatus to test the air-tightness performance of gasket-in-groove was designed,and a mechanical model to eval-uate the air-tightness failure behavior of gasket-in-groove was proposed,to investigate the air-tightness,as well as the failure mechanism of gasket-in-groove in actual engineering.The study shows that the results of the conceptual model match the experimental results,validating the feasibility and rationality of the conceptual model.The mechanism of joint gasket seal failure can be explained visually using the contact pressure path in the mechanical model.The sealing capaci-ty of the circumferential joint gasket is positively correlated with initial contact pressure,air-tightness factor,and gasket equivalent Poisson's ratio.The sealing capacity of the longitudinal joint gasket is positively correlated with air-tightness factor,gasket equivalent Poisson's ratio and tunnel outer diameter,while negatively correlated with gasket width.A higher initial contact pressure would result in a higher gasket sealing capacity,but a weaker sealing safety reserve.For the same conditions,the gasket sealing capacity of the longitudinal joint is markedly better than that of the circumferen-tial joint.
NETL
NSTL
万方数据
