A NEW TECHNIQUE FOR IN SITU STRESS MEASUREMENT BY OVERCORING

The Borre Probe was developed in Sweden, specifically to perform in situ stress measurements in fluid-filled boreholes drilled from the surface or underground. It has been used on various civil engineering and mining projects worldwide. This paper describes the Borre Probe and its operation, to emphasise its potential benefits to conventional site investigation. The probe measures the in situ stress from within a borehole, and uses nine electrical resistance strain gauges bonded directly to the walls of a pilot hole, drilled ahead of the main borehole. It also contains a thermistor and a dummy strain gauge, to permit assessment of the environmental effects on the gauges and their readings. It also contains a data logger, wholly contained within its body, which simplifies the operational aspects of the measurement and provides more detailed strain response data. It can be used in boreholes with a minimum diameter of about 76mm. Least squares analysis can be used to estimate the stress tensor from its strain gauges readings. The paper includes two case studies, including stress measurements for road tunnels in Stockholm, Sweden. It briefly discusses the method's measurement accuracy, and measurement of in situ stress at the depth of proposed underground caverns or tunnels during site investigation. For the covering abstract see IRRD 883023.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/0727725130
• Corporate Authors:

  Thomas Telford Limited

  London,   United Kingdom 
• Authors:
  • WHITTLESTONE, A P
  • LJUNGGREN, C
• Conference:
  • ADVANCES IN SITE INVESTIGATION PRACTICE. PROCEEDINGS OF THE INTERNATIONAL CONFERENCE HELD IN LONDON ON 30-31 MARCH 1995
• Publication Date: 1996

Language

• English

Media Info

• Features: References;
• Pagination: p. 499-509

Subject/Index Terms

• TRT Terms: Boreholes; Conferences; Data collection; Errors; Evaluation and assessment; Forecasting; Measurement; Measuring instruments; Regression analysis; Resistance (Electricity); Strain gages; Stresses; Tunnels
• Uncontrolled Terms: Site investigation
• Geographic Terms: Sweden
• ITRD Terms: 6155: Apparatus (measuring); 5711: Bore hole; 8525: Conference; 8623: Data acquisition; 6440: Error; 9020: Evaluation (assessment); 132: Forecast; 6136: Measurement; 6588: Regression analysis; 6916: Resistance (electr); 5722: Site investigation; 5562: Strain gauge; 5575: Stress (in material); 8109: Sweden; 3374: Tunnel
• Subject Areas: Bridges and other structures; Data and Information Technology; Planning and Forecasting;

Filing Info

• Accession Number: 00729284
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• ISBN: 0-7277-2513-0
• Files: ITRD
• Created Date: Dec 12 1996 12:00AM