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| Discussion on the Calculation and Control Methods of Water Pressure on Tunnel Lining |
| XIAO Ming-qing |
| (Underwater Tunneling Technology Hubei Engineering Laboratory, China Railway Siyuan Survey and Design Group Co. Ltd, Wuhan, Hubei 430063, China) |
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Abstract Abstract：Research purposes： The tunnel water drainage system will be blocked gradually due to various reasons during the long-term operation, and the secondary lining will subject to water pressure. The current calculation method of the water pressure on the lining is obtained from the two-dimensional model of cross sections, it’s necessary to study the longitudinal distribution characteristics of the water pressure on the lining and the control methods of the maximum water pressure basing on the space effect of the water-proofing and drainage system. Research conclusions： (1) For the structural water pressure obtained from the current two-dimensional model of cross sections, redistributions of water pressure will be formed after the consideration of space effects of the water-proofing and drainage system. (2) The maximum water pressure on the secondary lining of blocked sections is generally in direct proportion with the “margin” of underground water and the square of length of blocked sections, and inverse proportion with the product of the total area and the filtration coefficient of the drainage layer. (3) The recommended value of water pressure loads on the secondary lining: for mountain tunnels with small water drainage and maintenance operation difficulty, the water pressure may not be considered, or it shall be controlled within 0.05～0.15 MPa; for underwater tunnels and highway tunnels, it shall be controlled within 0.2～0.3 MPa, and it shall be controlled within 0.4～0.6 MPa for railway or subway tunnels. (4) “Pressure-relief rings” installed at a certain interval inside the tunnel are able to effectively control the maximum water pressure on the structure.（5）This research results will provide method of working mechanism for the water pressure on the lining and the control methods of the maximum water pressure.
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Received: 06 July 2017
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2017, Vol. 34 
