SUB CITY TUNNELS

The article discusses the complex interaction of vehicle tunnels within an urban environment. Taking the aspect of tunnel ventilation where artificial means ensure that potentially lethal exhaust fumes are diluted to acceptable levels, carbon monoxide concentrations at portals show that care should be exercised in portal location. While research work is proceeding on improving the environmental working conditions at the tunnel face, the results of a BRE/TRRL study show the need for developing seismic energy sources for advance monitoring of ground conditions. Although careful tunnelling in stable ground conditions can produce settlements of up to 30mm, larger settlements of up to 100mm can be experienced in unstable soil conditions. Such large surface settlements can be reduced using the bentonite tunnelling process - the first UK commercial use of which is to be made on an excavation at Warrington where ground movements will be monitored by TRRL. Research has shown that the merits of the tunnelling option can be increased by improving ground exploration, design, and construction methods, so reducing the environmental impact of their operation. /TRRL/

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00137727
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Apr 13 1977 12:00AM