Page - 739 - in Book of Full Papers - Symposium Hydro Engineering

GENERATION OF DAM SECTION The dam-sections were generated, satisfying the following requirements: • Compression throughout the entire foundation (i.e. the resultant force is within the central dam foundation) • FoS against sliding equal to 1.0. By changing crest width and downstream slope (see Figure 2) an optimal cross section was found using the “initial values” given in Table 1. Fig. 2. Dam section was selected by varying crest width and downstream slope. It was not possible to generate a cross section that satisfied the assumptions mentioned above. Therefore, the required FoS against sliding was increased from 1.0 to 1.1 as shown in the table below. Table 2. Geometry and FoS for dam-sections generated. Dam height [m] Crest width [m] Downstream slope [1:x] FoS Sliding Overturning 8 0.81 0.77 1.1 1.5 10 1.01 0.77 1.1 1.5 12 1.21 0.77 1.1 1.5 14 1.41 0.77 1.1 1.5 16 1.61 0.77 1.1 1.5 18 1.82 0.77 1.1 1.5 20 2.02 0.77 1.1 1.5 25 2.52 0.77 1.1 1.5 30 3.03 0.77 1.1 1.5 The above table shows that optimization of the cross sections provided a minimum FoS of 1.1 against sliding and 1.5 against overturning, with the assumptions used. In presentation of the results, the FoS for the initial dam section was normalized. This implies that the computed FoS against sliding was divided by 1.1, while the results against overturning was divided by 1.5. It can also be noted that when the friction angle was increased to 50º, the FoS against sliding increases to ~1.5, which is the same FoS as for overturning. 739