Engineering Rock Mechanics
1 28 Discontinuities 1.8- 1.6 1.4 1.2 h 1.0 x 0.8 0.6 0.4 0.2 Random spacing, Random spacing, random orientation orthogonal ...
Geometrical properties of discontinuities 1 29 I I I I I_---_---------- exposurej Figure 7.15 Diagrammatic representation of dis ...
1 30 Discontinuities JRC 1 3 I --- I 7 9 11 13 1s 17 19 0 5 10 cm I I I I I8 I, II Scale Figure 7.16 Barton’s Joint Roughness Co ...
Geometrical properties of discontinuities 1 3 1 along a scanline is independent of the position of other discontinuities), we ca ...
1 32 Discontinuities than or equal to 50 MPa, less than or equal to 25 MPa, greater than 25 MPa, or greater than 25 MPa and less ...
Geometrical properties of discontinuities 1 33 Proportionate error in mean discontinuity spacing, E Figure 7.18 Determination of ...
1 34 Discontinuifies For each discontinuity intersected by a scanline of trendlplunge as/&, measure dip directionldip angle ...
Mechanical properties 135 n U I Intact 6 U By definition, discontinuities have zero tensile strength t 6 I I 777 7 Figure 7. ...
136 Discontinuities between stress and displacement. However, for analysis it is convenient to assume either one global linear s ...
Mechanical properties 137 or u = kS. This final expression also permits evaluation of the displacements when the stresses are kn ...
1 38 Discontinuities 2.8 - Key A A parallel to surface ridges m B normal to surface ridges 2.4 - 2.0 - h Shear direction B A / / ...
Discussion 139 have described just the basic discontinuity geometry and behaviour here, but all the developments are likely to b ...
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8 Rock masses In this chapter, we will concentrate on extending the ideas discussed in the previous chapter on discontinuities t ...
142 Rock masses deformation of the intact rock; the other due to the deformability of the discontinuities. The contribution made ...
Deformability 143 The case illustrated via the mathematics above and shown in Fig. 8.2 only involves loading parallel to the dis ...
144 Rock masses diagram, the minimum moduli are in a direction perpendicular to the sets, and the maximum moduli are at a direct ...
Substituting these into the Mohr-Coulomb criterion, I TI = cw + on tan &, and rearranging gives where cw and &,, are the ...
146 Rock masses Figure 8.6 Strength of a rock mass containing multiple discontinuity sets. We can consider, on the basis of this ...
Post-peak sfrengfh behaviour 147 Table 8.1 Approximate relations between rock mass quality and the material constants in the Hoe ...
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