Journal Published Online: 20 March 2023
Volume 51, Issue 5

Airtightness Performance Test and Failure Models for Low-to-Vacuum Maglev Train Tunnel Joints

CODEN: JTEVAB

Abstract

The airtightness at the joints of segment lining structures is one of the critical problems for low-to-vacuum maglev train tunnels that needs to be addressed. A new apparatus was designed to test the airtightness performance of the gasket-in-groove at longitudinal and circumferential joints. Based on the test results, four mechanical models based on the theory of elastic mechanics were developed to describe the short-term and long-term sealing failure behaviors of longitudinal and circumferential joints, which are subjected to vacuum pressure on one side of the gasket, and the corresponding air-leakage equations for contact interface were also deduced. The test results show (1) a higher initial contact pressure in the gasket-in-groove would result in faster stress relaxation; (2) a greater initial contact pressure would result in better joint sealing; and (3) for the same initial contact pressure, the sealing capacity of longitudinal joints is significantly better than that of circumferential joints. The test results are in good agreement with the models. The developed models can be used to interpret the sealing failure mechanism through the gasket contact pressure path. Moreover, the mechanical models show that the sealing capacity of the circumferential joint gasket is positively correlated with the airtightness coefficient and the gasket equivalent Poisson’s ratio, whereas the sealing capacity of the longitudinal joint gasket is positively correlated with the airtightness coefficient, the gasket equivalent Poisson’s ratio, as well as the tunnel outer diameter, and negatively correlated with the gasket width.

Author Information

Shi, Long
School of Civil Engineering, Southwest Jiaotong University, Chengdu, China
Wang, Dongyuan
Key Laboratory of High-Speed Railway Engineering, Ministry of Education, Southwest Jiaotong University, Chengdu, China
Zhou, Jianjun
State Key Laboratory of Shield Machine and Boring Technology, Zhengzhou, China
Cui, Kai
Key Laboratory of High-Speed Railway Engineering, Ministry of Education, Southwest Jiaotong University, Chengdu, China
Pages: 15
Price: $25.00
Related
Reprints and Permissions
Reprints and copyright permissions can be requested through the
Copyright Clearance Center
Details
Stock #: JTE20220665
ISSN: 0090-3973
DOI: 10.1520/JTE20220665