Engineering Rock Mechanics

236 Rock mechanics interactions and rock engineering systems (RES)

Normal

Wrench

c3

0 Block moving towards observer

I Youngest fault Block moving away from observer

1 Oldest fault

• Vertical fault

Sense of shear along wrench fault

s

boo Fault dipping 30' in direction of tick

Figure 14.14 Binary combinations of normal, wrench and thrust faults (produced

with help from Dr J. W. Cosgrove).

We have also presented some information in parts of the book using the

interaction matrix concept, as for example Fig. 10.1 to consider the

connections between the attributes of discontinuousness, inhomogeneity,

anisotropy and non-elasticity.

14.7 Concluding remarks

The interaction matrix is the basic device used in rock engineering systems.

For a rock engineering project, the most important step in the RES

methodology is to establish the objectives of the project and the analysis.

Once that has been done, the relevant 'state variables' are chosen-i.e. the

terms to place along the leading diagonal of the interaction matrix. In

some problems, these variables have to be more conceptual in nature;

in some problems, there may be enough information to use well-defined

physical properties with definite units. Then, all the interactions are