A rational design of steel segmental lining in large dimensional shield tunnels for rapid post-excavation method

The Central Circular Shinjuku Route (total length: 11 km), which is now under construction, is composed of a tunnel structure for most of the route and the large dimensional shield method is used for 70% of the total route. Five out of eight ramp or junction sections of the route, such as the entrances and exits, are planned to be constructed in the shield tunnel sections. For the construction of a ramp or junction section, the cut-and-cover method for shield tunnels with cutting steel segments will be used. With this method, after two shield tunnels are constructed in parallel with each other, the ground over the ramp or junction section is excavated from the ground surface by cut-and-cover method. Then, a part of steel segments of each tunnel is cut open and reinforced concrete frame body for the ramp or junction section will be constructed there. Except for some examples in the construction of subway stations, this is the first case of cutting a shield tunnel open among road tunnels in Japan. Some problems were considered in designing for the steel segment of the cut open part and the measures stated below were applied for dealing with the problems: (a) Appropriate modeling of steel segments and frame body: The cut-and-open section is a composite structure consisting of reinforced concrete frame body and steel segments. The entire structure composed of steel segments and the frame body should be modeled together to evaluate the rigidity of the entire composite structure appropriately. Namely, the frame body was represented by solid elements and the steel segments by beam elements with uniform rigidity. Using this model, the stress resultant near the connection of the steel segment to the frame body was evaluated appropriately. (b) Evaluation of decrease in rigidity of frame body: The deformation of the frame body of the reinforced concrete structure increases after completing the construction. This is because its flexural rigidity is decreased due to creep and traverse tension cracks. This deformation has a great influence on stress resultants of steel segments. Therefore, the design of the steel segment has been done considering the influence of the deformation. (c) Evaluation of preceding stress arisen during construction: The construction of the ramp or junction sections goes through complex procedures. In each stage of the construction, the steel segments have several conditions of deformation and stress. The design of steel segments, that are based on the appropriate evaluation of the preceding stress arisen during the construction, was carried out using a sequential analysis that considers the construction history. (A). "Reprinted with permission from Elsevier". For the covering abstract see ITRD E124500.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/08867798
• Authors:
  • DOBASHI, H
  • KAWADA, N
  • SHIRATORI, A
  • YAMANAKA, H
  • MORI, M
• Publication Date: 2004-7

Language

• English

Media Info

• Pagination: 457-8
• Serial:
  • TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY. UNDERGROUND SPACE FOR SUSTAINABLE URBAN DEVELOPMENT. PROCEEDINGS OF THE 30TH ITA-AITES WORLD TUNNEL CONGRESS SINGAPORE, 22 - 27 MAY 2004
  • Volume: 19
  • Issue Number: 4-5
  • Publisher: Elsevier
  • ISSN: 0886-7798

Subject/Index Terms

• TRT Terms: Conferences; Excavation; Steel; Tunnels
• ITRD Terms: 8525: Conference; 5155: Excavation (process); 4542: Steel; 3374: Tunnel
• Subject Areas: Bridges and other structures; Design; I25: Design of Tunnels;

Filing Info

• Accession Number: 01011619
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• Files: ITRD
• Created Date: Dec 19 2005 3:21PM