STRENGTH AND DEFORMABILITY OF HIGHLY FRACTURED ROCK

This paper reviews procedures used to determine properties of the grey wacke sandstone forming the foundation of a concrete dam. Multistage triaxial testing of carefully reassembled core specimens provided a series of shear-strength versus normal-stress curves for fractured rock; the lowest of these was adopted as representative of the strength of the rock mass. Deformability was measured during the triaxial tests and in the field using a borehole jack in 3-in. (76-mm) drill holes. The latter yielded a value for the normal stiffness of the fractures in the rock. Introducing this stiffness value together with any given fracture spacing then determined the rockmass modulus of elasticity corresponding to the assigned fracture spacing. Longitudinal and shear-wave velocity measurements in cross-hole configuration determined modulus of elasticity values considerably higher than those measured with the borehole jack, as expected in fractured rock. (ASCE)

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  • Accession Number: 00308183
  • Record Type: Publication
  • Report/Paper Numbers: ASCE 14988
  • Files: TRIS
  • Created Date: Mar 12 1981 12:00AM