PORE-PRESSURE RESPONSE IN ROCK TO UNDRAINED CHANGE IN ALL-ROUND STRESS

Pore-water pressure response in saturated intact specimens of berea sandstone, Salem limestone, Vermont marble and Barre granite to undrained increase in all-round stress, was measured in a specially designed triaxial cell. Dense intact rock specimens exhibited values of SKempton's b coefficient near at small effective all-round stresses, However, as effective stress increased, b coefficient rapidly decreased. Based on the measurements, corrected for the compressibility of the pore-pressure measuring system, the values of b at effective stress of 1600 lb/sq.in were in the range of 0.33-0.69. The rapid decrease in pore-pressure response at the effective all-round stress range of 0-500 lb/sq.in is attributed to closure of crack-type pores and the corresponding decrease in compressibility of the rock skeleton. It is concluded that bishop's expression for the B coefficient with appropriate values of the compressibility of the rock skeleton can predict the pore-pressure response in rocks with interconnecting pores. The major problem in computation lies with the proper choice of values for the compressibility of the rock skeleton. /TRRL/

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 317-330
  • Serial:
    • GEOTECHNIQUE
    • Volume: 26
    • Issue Number: 2
    • Publisher: Thomas Telford Limited
    • ISSN: 0016-8505

Subject/Index Terms

Filing Info

  • Accession Number: 00142441
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Report/Paper Numbers: Analytic
  • Files: ITRD, TRIS
  • Created Date: Jul 19 1977 12:00AM