Abstract: A stochastic analysis method was worked out for structural response to predict the dynamic response value, to determine the reasonable safety distance based on a statistical model. Firstly, a statistical load model was built based on the existing blast load prediction formula, data charts and related tests. Then, an explosive-air-dam -foundation finite element model was also built for a non-overflow section of a certain concrete gravity dam in China and the uncertain dynamic response of the structure of the dam was analyzed. Finally, the statistical distribution of the dynamic response values and the percentage damage,as functions of the scaled distance,were studied. The results indicate that peak responses of the dam roughly obey normal distribution, so the uncertainty of explosion load should be considered in analyzing the damage of the structure under the explosive impact.

Key words: concrete gravity dam, blast loading, air blast, dynamic response, anti-explosion protection design