13th International Conference on Fracture June 16–21, 2013, Beijing, China -5- (a) 1.5 times water pressure (b) 2.0 times water pressure Figure 5. Cracking status of the dam heel near river bed area 3.2. Fracture analysis of Xiaowan arch dam Xiaowan arch dam is subjected to numerous cracks due to the temperature control program. In the following example, we simulate the major cracks in the dam and analyze parameters sensitivity with DRT method. Results and conclusions of geo-mechanical model test are also given as comparison with numerical method. FE computation model of Xiaowan includes 58989 nodes and 53850 elements, while 11 cracks in the dam are simulated with thin layer elements, as shown in Fig. 6. Since engineering measures have been applied, the parameters of crack elements are as follows: E=5GPa, μ=0.3, γ=27.5kN/m3, f=1.12, c=0.9MPa. Parameters E, f, c are reduced with certain percentages in five schemes, respectively 100% (scheme 1), 50% (scheme 2), 30% (scheme 3), 10% (scheme 4) and 5% (scheme 5). Both normal and overload conditions are included in each scheme. Unbalanced forces of cracks and dam heel in scheme 1 and 3 are given by Table 1 and Table 2. Figure 6. Distribution of cracks in Xiaowan arch dam Table 1. Unbalanced forces of cracks and dam heel in scheme 1 (104 N) No. Crack Dam weight Water pressure 1.5 times water pressure 2 times water pressure 2.5 times water pressure 1 13lf-1 0.06 0.00 0.36 1.36 32.50 2 13lf-2 0.01 0.00 1.23 4.84 76.41 3 20lf-1 0.02 0.00 0.00 0.00 13.92 4 20lf-2 0.00 0.00 0.58 6.63 11.95 5 22lf-1 0.00 0.00 0.00 0.00 0.00 6 22lf-3 0.00 0.00 0.00 0.00 0.00 7 22lf-4 0.00 0.00 0.00 0.00 0.00 8 25lf-1 0.00 0.00 0.00 0.00 1.04 9 28lf-1 0.01 0.00 0.00 0.00 3.99 10 28lf-2 0.05 0.00 1.91 13.10 24.79 11 30lf-1 0.00 0.01 0.41 16.73 29.77 Dam heel 4122.63 40249.56 257289.9 415601.5 561660.5 * Crack 13lf-1 in the table means the first crack in No. 13 dam section, and so on. dam dam crack crack
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