Coupling of Stress-Strain Behavior and Seepage Flow - Rock Mechanics Based on an Anisotropic Jointed Rock Model - page 166

Figure 7.1 Gravity dam on jointed rock, equipotentials (Erichsen 1987)
In case of a double curved arch dam the self-weight of the dam will be mainly verti-
cally transferred towards the valley bottom, whereas arching is mainly effective for
the load of the impounded water reservoir. Thus, the water load to a large degree
is transmitted to the abutments. The stress concentrations underneath an arch dam
foundation are generally larger than underneath a gravity dam. Consequently,
larger permeability changes are to be expected.
As a further example for hydromechanical interaction, an artificial cut in the rock
mass with horizontal, bedding-parallel discontinuities and vertical joints striking
parallel to the slope is considered. The excavation of the cut leads to a lowering of
the water table. In addition, tensile stresses adjacent to the crest and shear stresses
near the toe of the slope, resulting from the excavation, may lead to an increase
in the rock mass permeability within these zones. Thus, accounting for the stress
dependency of the rock mass permeability the lowering of the water table is more
pronounced compared with the case where the stress dependence of the rock mass
permeability is ignored (Fig. 7.2).