GROUND FREEZING DEALS WITH TUNNEL INSTABILITY

Two case studies are described where tunnel operations were halted due to adverse ground conditions and ground freezing techniques were successfully applied. In Sunderland, during a tunnelling operation an undetected depression in the clay surface was encountered. The construction operations become partially flooded and tunnelling had to be abandoned. Completion of the tunnel was accomplished by creating a frozen arch bridging the gap, beneath which the heading could be completed. Freeze tubes were installed and refrigeration was conducted from the surface. The complete operation-drilling, refrigeration and excavation-lasted 26 days. On the Isle of Grain, a cable tunnel was being driven from the Isle of Grain under the Medway to the Chetney Marshes. The western tunnel experienced an inrush of sand, silt, and shell debris. Exploratory core drilling indicated a sand/shell filled fissure in the London Clay. Porewater pressure fluctuated with tidal variations indicating a connection between the feature and the river bed. Freeze tubes were installed and tunnelling resumed in stages when monitoring of the advance of the ice-wall indicated that satisfactory mining conditions existed.

• Availability:
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• Corporate Authors:

  Foundation Publications Limited

  7 Ongar Road
  Brentwood CM15 9AU, Essex,   England 
• Authors:
  • Harris, T S
  • Woodhead, F A
• Publication Date: 1977-9

Media Info

• Features: Figures; Photos; References;
• Pagination: p. 47-48
• Serial:
  • GROUND ENGINEERING
  • Volume: 10
  • Issue Number: 6
  • Publisher: EMAP CONSTRUCT LIMITED
  • ISSN: 0017-4653

Subject/Index Terms

• TRT Terms: Clay; Cracking; Excavation and tunneling; Floods; Freezing; Soil stabilization; Tunneling
• Uncontrolled Terms: Depressions (Indentations)
• Old TRIS Terms: Freezing processes
• Subject Areas: Bridges and other structures; Geotechnology; Highways; Hydraulics and Hydrology;

Filing Info

• Accession Number: 00170433
• Record Type: Publication
• Files: TRIS
• Created Date: Apr 12 1978 12:00AM