低真空隧道管片接缝密封垫气密性试验及力学模型
Air-tightness Test and Mechanical Model of Gasket at Segment Joint of Low Vacuum Tunnel
石龙 1周建军 2王东元 1吕乾乾2
作者信息
- 1. 西南交通大学 土木工程学院,四川成都 610031
- 2. 中铁隧道局集团有限公司盾构及掘进技术国家重点实验室,河南郑州 450001
- 折叠
摘要
管片式衬砌结构作为构建列车低真空运行环境的一种合理方案,其接缝处的气密性是需要解决的关键问题之一.针对该问题,设计一套测试垫片-垫片槽气密性能的试验装置,提出一种评估垫片-垫片槽气密失效行为的力学模型,以实际工程垫片-垫片槽为研究对象,分析其气密性以及失效机理.研究结果表明,力学模型结果与试验结果相吻合,验证了力学模型可行性和合理性;利用力学模型中接触压力路径,可以直观解释接缝垫片密封失效机理;环向接缝垫片密封能力与初始接触压力、气密性系数、垫片等效泊松比呈正相关;纵向接缝垫片密封能力与气密性系数、垫片等效泊松比和隧道外径呈正相关性,而与垫片宽度呈负相关;初始接触压力越大,垫片密封能力越强,但密封安全储备越弱;同等条件下,纵向接缝垫片密封能力明显优于环向接缝.
Abstract
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.
关键词
低真空隧道/管片衬砌结构/气密性试验/力学模型/失效机理Key words
low vacuum tunnel/segment lining structure/air-tightness testing/mechanical model/failure mechanism引用本文复制引用
基金项目
盾构及掘进技术国家重点实验室开放课题(SKLST-2019-K04)
中国中铁股份有限公司科技研究开发计划(2020-重点-27)
中铁隧道局集团科技创新计划(隧研合2018-08)
出版年
2024
NETL
NSTL
万方数据