Swelling Rock - Rock Mechanics Based on an Anisotropic Jointed Rock Model - page 205

Figure 8.21 Principle of resisting support, finite element mesh and boundary conditions (Wahlen 2009)
Figure 8.24 shows the comparison of measured and calculated water consumption ver-
sus time. At the beginning of irrigation, the water uptake was dominated by seepage
flow. After sealing of the rock mass near the boreholes, the rate of water uptake de-
creased. Since that, water uptake was governed by the diffusion process, and a linear
increase in water consumption with time was measured. This could be reasonably con-
firmed by the analysis. Also, a good agreement between the measured and calculated
heaving of the invert versus time could be achieved (Fig. 8.25).
Figures 8.26 and 8.27 show the comparison of measured and calculated water con-
sumption and heaving of the invert versus time for a block constructed according to the
principle of yielding support. Here also, a reasonable agreement between measurement
and analysis could be achieved.
These results show that the model represented in this chapter could be calibrated on
the results of long-term measurements in the test gallery for the Freudenstein tunnel
and allows us to verify the self-sealing effect due to swelling around a tunnel which is
constructed according to the principle of resisting support (Wittke 2003, Wittke 2004,
Wittke 2006, Wittke et al. 2007).