** **

**6.4.1
Continuum versus discontinuum models**

In general, slope stability problems involve discontinuities at one scale or another. If rock mass of slope can be represented as an equivalent continuum, continuum models should be used to solve these types of problems (figure 12). Therefore, many analyses begin with continuum models. If the slope under consideration is unstable without structure, there is no point in going to discontinuum models (figure 13).

In contrast to the above, if the discontinuities can be represented in terms of equivalent rock mass properties and the number of intersecting joints are large, than discontinuum code may provide better solution. However, these models require in-depth knowledge of the properties of discontinuities of rock and their mutual interaction and are very difficult to determine. Therefore, one can go for simulation of rock slope mass by using continuum code in many cases.

Figure 12: 2D simulation of bench slope by FLAC based on finite difference method

* *

* *

Figure 13: 3D simulation of slope 3DEC software based on discontinuum modeling