Page - 1359 - in Book of Full Papers - Symposium Hydro Engineering

Fig. 11: Settlements after first impounding The deformation behaviour of dams with a thin impervious central membrane is mainly governed by the dam zoning, material stiffness and shear strength as well as the dam foundation conditions (stiffness, surface inclination). Figure 11 shows the settlements of the analysed dam for the first impounding. Since the stiffness of the asphalt concrete core is generally lower than the stiffness of the adjacent zones, the settlements of the core are governed by adjacent dam zones. The graph shows that the settlements after impounding are concentrated upstream. Figure 12 depicts the horizontal deformations of the analysed dam. Due to impounding, the additional water load, acting on the core leads to a horizontal deformation of the core to the downstream side. The magnitude of those displacements depends on the resistance (stiffness and shear strength) of the downstream shoulder. The largest horizontal deformations occur in the upper part of the dam. The graph clearly shows the mobilization of a wedge in the upstream dam shoulder which is triggered by the downstream deformation of the core due to impounding. Fig. 12: Horizontal deformations: end of construction and first impounding 1359