FOAM AS A TUNNELLING AID: ITS PRODUCTION AND USE

Water-based foams are now being used in construction, especially for the conversion of cement mortars and grouts into foam concrete. This article discusses the use of wet foams to assist tunnelling operations. A typical wet foam generator has: (1) solution and foaming agent pumps; (2) a compressed air meter; (3) flow meters and controllers; and (4) a conditioner or lance which converts the fairly coarse foam, produced in the mixing chamber, into a microcellular form. Other types of foaming system are available. For use as a tunnelling aid, foam needs to satisfy the following criteria. The foam must lubricate the cutters of the tunnelling machine, thus reducing the torque needed during excavation. In microtunnelling operations, the foam should also lubricate the drive pipe during a drive. The foam should keep pieces of cut minerals discrete, especially in clay, to minimise remoulding and balling up in the cutterhead. When excavating in clay, the foam should seal cut surfaces to avoid water take-up and swelling. When excavating in sands or gravel, the foam should form a waterproof mass of soil and minimise infiltration rates. The foaming agent should be environmentally friendly in use and after removing spoil. The mixing chamber and lance should be designed for delivery pressure up to 16bar to clear any blockages.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/0041414X
• Corporate Authors:

  Morgan-Grampian Limited

  30 Calderwood Street
  London SE18 6QH,   England 
• Authors:
  • CASH, T
  • VINE-LOTT, K M
• Publication Date: 1996-4

Language

• English

Media Info

• Pagination: p. 22-3
• Serial:
  • Tunnels & Tunnelling International
  • Publisher: Progressive Media Markets, Ltd
  • ISSN: 0041-414X

Subject/Index Terms

• TRT Terms: Cement; Clay; Concrete; Construction management; Equipment; Expanded materials; Full face tunneling; Gravel; Grout; Mortar; Pumps; Sand; Tunneling machines; Tunnels; Water; Waterproofing
• ITRD Terms: 4758: Cement; 4177: Clay; 4755: Concrete; 3666: Construction method; 3674: Equipment; 4502: Expanded material; 3383: Full face tunnelling machine; 4575: Gravel; 4729: Grout; 4769: Mortar; 3833: Pumping; 4105: Sand; 3374: Tunnel; 4355: Water; 3375: Waterproofing
• Subject Areas: Bridges and other structures; Construction; Materials;

Filing Info

• Accession Number: 00725492
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• Files: ITRD
• Created Date: Sep 26 1996 12:00AM