Abstract: As the mechanical parameters of concrete dam obtained by indoor test deviates largely from measured values, back analysis of parameters using optimization or bionic algorithm based on measured deformation is adopted in practical engineering. To address the nonuniqueness of parameter inversion, we propose to obtain the probability distribution function of multiple back analysis results based on measured deformation via probability statistical approach, and then determine the inversion parameters according to 80% guarantee rate. The proposed method is verified by the measured deformation values of a roller compacted concrete (RCC) dam in high and cold region. The method provides stable mechanical parameters of dam body and dam foundation, and offers a reference for the safety assessment of RCC dam in high and cold region.

Key words: back analysis of parameters, nonuniqueness, probability statistical analysis, strength standard value, RCC dam