RELIABILITY PROBABILISTIC ASSESSMENT OF CONCRETE GRAVITY DAM ON ROCK FOUNDATION OF SUSTAINABILITY CRITERIA IN DAM AGAINST THE SHIFT ANDOVERTURNJournal: Academic Journal "Industrial Machine Building, Civil Engineering" (Vol.3, No. 45)
Publication Date: 2015-12-25
Authors : Balabai O.;
Page : 203-211
Keywords : concrete dam; the probability and reliability.;
Several accidents concrete gravity dam on rock foundations encouraged to address the problem of reliability of such bases, previously considered ideal. Mechanical properties determine the behavior of rocks under the influence of external forces on them ? loads. These properties allow to directly evaluate the strength and deformation rocks. Due to disturbances in the basics held 38% of the total destruction of concrete gravity dams, 10% of accidents occurred due to an increase in permeability rocks. Because of the heterogeneity of deformation in co-operation structures and foundations of hydrostatic loads on 22% of accidents concrete dams. The paper discusses the methodology of probabilistic safety assessment of concrete gravity dam on rock foundation for the stability criterion dam against shifting and tilting. The result is a quantitative assessment of the probability of the ultimate state of the first group of limit states associated with the loss of resistance to shear and overturning. The method was tested on the example of a high concrete gravity dam hydroelectric Big Energy Ethiopian renaissance dam on r. Blakitny Nile in Ethiopia, projected by PJSC Ukrhydroproject. Marking the top concrete dam +645.000 m, total length of 1,783 m. Grassroots facet dams speed of incorporation 0.8.The basis of the dam are rock solid bedrock - gneiss. Calculations are performed for basic and special combination of loads and impacts. To solve this problem the method applied statistical tests (Monte Carlo). In this case, use the following method of calculation at every statistical tested in j (j = 1,2, ..., n): 1. For each of the output random variables and the number (i = 1,2, ..., n) are set uniformly distributed in the range from 0 to 1 random probability Pi,j. 2. According to the obtained values Pi,j using the distribution function arguments are values Xi,j each of the random variables. 3. For known values Xi,j according to equation connection value calculated total factor Yj. 4. Checking of implementation of relevant conditions to achieve the ultimate state of total value received by the factor. Found on probabilistic method the probability of loss of stability of the dam against shear, the probability of loss of stability of the dam against overturning. It determines the number of statistical tests to achieve a fairly narrow confidence interval. In this paper put forward the assumption that the calculation of the strength that the foundations should be carried out on the basis of the calculation of resistance against capsizing concrete structures on the rock on the scheme boundary rotation. The proposed method can be used in the calculation of concrete gravity dam on rock foundation.
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