These components act on each visible face of an infinitesimal cube used to represent a point within a rock mass. This results in a total of nine stress components that can be organized in a 3x3 matrix, called the stress tensor (see figure 4). Assuming the rock is at rest, the stresses of equal magnitudes and opposite directions will cancel out each other and prevent the cube from rotating. There is a special orientation in space where all shear stresses equal to zero and only three normal compressive components exist, called principle stresses (see Figure 5). The three principle stresses are the vertical stress (σV), the maximum horizontal stress (σH), and the minimum horizontal stress (σh). | These components act on each visible face of an infinitesimal cube used to represent a point within a rock mass. This results in a total of nine stress components that can be organized in a 3x3 matrix, called the stress tensor (see figure 4). Assuming the rock is at rest, the stresses of equal magnitudes and opposite directions will cancel out each other and prevent the cube from rotating. There is a special orientation in space where all shear stresses equal to zero and only three normal compressive components exist, called principle stresses (see Figure 5). The three principle stresses are the vertical stress (σV), the maximum horizontal stress (σH), and the minimum horizontal stress (σh). |