Stability of Rock Wedges and Excavation Surfaces - Rock Mechanics Based on an Anisotropic Jointed Rock Model - page 309

Fig. 11.19 shows the geometry of such a rock wedge with height h. The orientations of
D1 and D2 are described by the angles α 1 , α 2 and β 1 , β 2 . These are related to the strike

angles α D1 , α D2 and dip angles β D1 , β D2 introduced in Section 2.7.2 as follows:

(11.44)

(11.45)

(11.46)

(11.47)

Figure 11.19 Three-dimensional rock wedge supported by two discontinuities D1 and D2, geometry
(Wittke 1990)

where α S is the angle between north and the strike direction of the slope, which is not

represented in Fig. 11.19. The slope is inclined at an angle ε to the horizontal above the

slope toe and at δ to the horizontal above the slope crest. The relationships given below

are valid for

0 < ε < 180°, (11.48)

0 < δ < 90°, (11.49)

δ < ε . (11.50)