Stability of Rock Wedges and Excavation Surfaces - Rock Mechanics Based on an Anisotropic Jointed Rock Model - page 308

Using the general wedge method, the wedge can be stabilized by an anchor force of
A d = 200 kN/m yielding a utilization factor of μ GWM = 0.92. This force can be applied

for example by means of tendons on one row with an anchor force of 200 kN/m (Fig.
11.17, upper) or by two rows each with an anchor force of 100 kN/m (Fig. 11.17, lower).

11.3.2 Three-Dimensional Rock Wedges

Sliding of a three-dimensional rock wedge supported by one or two discontinuities
Next, the stability against sliding of a rock wedge bounded by the surfaces Sl u and S l
of a slope and two discontinuities D1 and D2 will be investigated (Fig. 11.18). The
unit vectors {t} describing potential translations can run parallel to both discontinui-
ties (sliding parallel to the line of intersection), can run parallel to D1 or D2 or may be
pointing away from both discontinuities (Fig. 11.18, upper). The case of sliding parallel
to the line of intersection is illustrated in Fig. 11.18 (lower).

Figure 11.18 Potential
translations of a three-dimensional
rock wedge supported by two
discontinuities (Wittke 1990)