METHOD TO ANALYZE HYDRAULIC FRACTURING IN EARTH CORE ROCK-FILL DAM AND ITS APPLICATION BASED ON PROBABILISTIC APPROACH

Hydraulic fractures can lead to concentration leakage, which can influence normal operation of dam, even cause to break down dam. At present, deterministic method is employed to analyze hydraulic fracturing. Because characteristics of earth and rock show great variability, the results obtained using deterministic method can not reliably indicate whether earth core can be fractured by water pressure or not. The effects of variability of dam materials on hydraulic fracture in the core can be considered in probabilistic methods. According to probability distribution of physical parameters of dam materials, hydraulic fracturing criterion is used to construct the function of hydraulic fracturing in the core. Accordingly reliability index of hydraulic fracturing in the core is calculated through Geometry Method, and probability of hydraulic fracturing can be obtained. Taking one earth core rock-fill dam for example, the method mentioned above is used to analyze hydraulic fracturing in the core. The results suggest that probability of hydraulic fracturing in the core increase with great variability of Poisson's ratio, density of dam materials, and contribution of variation of elastic module to hydraulic fracturing in the core is weak. In addition the effect of water filling rate on the potential of hydraulic fracturing in the core is also analyzed.