DEFORMABLE SPHERICAL DEVICES TO MEASURE STRESSES WITHIN FIELD SOILS

The design, calibration and use of two deformable spherical stress transducers are described. They are suitable for detecting principal stresses in deforming media such as soil and have major advantages over many rigid transducers previously used in such situations. One of the transducers is a water-filled rubber ball (wfrb) sensitive to hydrostatic and deviator stresses, the other is a mastic ball which deforms plastically and is sensitive to only deviator stresses. When the two devices are used at similar depths under a surface load, e.g. A wheel, the combined measurements of internal pressure of the wfrb and axial deformation of the mastic ball can be used to derive values for first and third principal stresses (assuming second and third principal stresses are equal). Calibrationof the transducers at different temperatures is described. Field measurements made with the transducer under loaded wheels are compared with predicted values of first principal stresses using equations developed by Soehne. Close correspondence between predicted and measured values was observed, when the existing soil strength conditions were taken into account. The transducers promise to be useful in the measurement of stresses in field soils. (Author/TRRL)

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/00224898
• Corporate Authors:

  Pergamon Press, Incorporated

  Headington Hill Hall
  Oxford OX30BW,    
• Authors:
  • Blackwell, P S
  • Soane, B D
• Publication Date: 1978

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 207-222
• Serial:
  • JOURNAL OF TERRAMECHANICS
  • Volume: 15
  • Issue Number: 4
  • Publisher: Pergamon Press, Incorporated
  • ISSN: 0022-4898

Subject/Index Terms

• TRT Terms: Calculation; Calibration; Deformation; Field tests; Loads; Measurement; Measuring instruments; Soil mechanics; Soils; Spheres; Strength of materials; Stresses; Temperature; Transducers
• Uncontrolled Terms: Balls
• ITRD Terms: 5197: Ball; 6464: Calculation; 6171: Calibration; 5595: Deformation; 6226: In situ; 5567: Load; 6136: Measurement; 4156: Soil; 5544: Strength (mater); 5575: Stress (in material); 6722: Temperature; 6140: Transducer
• Subject Areas: Geotechnology; Highways;

Filing Info

• Accession Number: 00335240
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• Files: ITRD, TRIS
• Created Date: Oct 28 1981 12:00AM