6.6 Concluding Remarks

We have presented three failure criteria that are extensively used in rock mechanics and rock engineering. The reader should be aware of the shortcomings of each of the criteria, and be prepared to make use of whichever is best suited to a particular application. Further criteria are available as listed in Fig. 6.21. None of the criteria take into account the specific structure of the rock mass, in particular its fracturing configuration. The occurrence of the natural pre-existing fractures in rock masses is the next subject to discuss because of their profound influence on the deformation, strength and failure of rock masses.

Figure 6.21: Summary of rock failure criteria up to 1988 (from Pan, 1989).