Safety Factor (Hoek-Brown)

The strength criterion, or, in other words, the failure criterion Hoek-Brown was developed specifically for the design of underground workings.

In this example, we will analyze the problem of uniform compression of a square. Since the model is symmetrical in both directions, then to solve it is enough to consider only its quarter and set the boundary conditions corresponding to symmetry in the form of displacements.

It makes sense to calculate the safety factor in the case when the task is nonlinear. In order for the filter to become active in FidesysViewer, it is necessary in the preprocessor in the calculation settings Static - Output Fields to check the Output material properties box (Fig. 1).

Fig. 1. Solver settings

Fig. 2 shows the calculation scheme.

Fig. 2. Calculation scheme

To see the safety factor, you will need to open the pvd-file.

Analysis of the results in FidesysViewer

In the opened FidesysViewer window you will be able to see the calculation results (Fig. 3).

Fig. 3. Calculation results

Before you do anything, make sure that the file you want is selected in the tree and highlighted in blue, as in Fig. 4. Then apply the "Safety Factor" filter.

Fig. 4. Filter «Safety Factor»

In the "Safety Factor" properties panel, check the "Hoek-Brown theory" box and click Apply, as shown in Fig. 5.

Fig. 5. Selecting attributes of the “Safety Factor” filter

Fig. 6 shows the isofields of the safety factor according to the Hoek-Brown theory. Since the example considers uniform compression, the distribution of the safety factor is also uniform.

Fig. 6. Safety Factor

In cases where the distribution of the safety factor is non-uniform and you need to find its average value, then you need to use the "Statistics" filter (Fig. 7).