SUGGESTED METHODS FOR DETERMINING IN SITU DEFORMABILITY OF ROCK

Three methods are presented: (1) the plate test which uses superficial loading, often referred to as the uniaxial jacking test or plate jacking test, and is performed in small tunnels or test adits - two areas each approximately 1 M in diameter, are loaded simultaneously using jacks positioned across the tunnel; rock mass deformations are measured in boreholes behind each loaded area and across the tunnel between each loaded area. (2) use of the plate test down a borehole - successively higher bearing pressures, in loading and unloading cycles, are applied to the flattened end of a borehole and the resulting rock displacements are recorded. The method is usually employed to provide information for the design of foundations where access to the proposed foundation level cannot readily be obtained by an exploratory trench or adit; and (3) a radial jacking test, in which a test chamber of circular crass section is subjected to uniformly distributed radial loading; the consequent rock displacements are measured, from which elastic or deformation modulae may be calculated. A large volume of rock is loaded, so that the results may be taken to represent closely the true properties of the rock mass, the anisotropic deformability of the rock can also be measured (not possible with method 2). The results are usually employed in the design of dam foundations and for the proportioning of pressure shaft and tunnel linings. /TRRL/

  • Availability:
  • Corporate Authors:

    Pergamon Press, Incorporated

    Headington Hill Hall
    Oxford OX30BW,   England 
  • Publication Date: 1979-6

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00301985
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, TRIS
  • Created Date: Nov 27 1979 12:00AM