Finite Element Method (FEM) - Rock Mechanics Based on an Anisotropic Jointed Rock Model - page 281

m/s and = 10 -6 m/s, respectively, in horizontal and vertical direc-
tion of the alternating sequence (Fig. 10.56).
Because the thicknesses of the Oolithenbank and the Psilonotenbank cannot be ne-
glected compared with the tunnel diameter, these limestone layers were discretely sim-
ulated in the analyses with a permeability coeffi cient of (Fig. 10.56).

Figure 10.57 Drawdown of water table (Wittke 2000b)

Since the results of the permeability tests carried out in the claystone reveal a large scat-
ter, the permeability coeffi cient of the claystone was varied from k = 10 -7 m/s (cases 1, 3
and 4) to k = 10 -6 m/s (case 2) in the analyses (Fig. 10.56).
The shotcrete membrane was assumed to be impermeable in cases 1 and 2. In case
3, a permeability of the shotcrete membrane of 10 -8 m/s was assumed. According to
Kramer (1988), this value is close to reality. In case 4, a complete permeable shotcrete
membrane was investigated for comparison (Fig. 10.56).