Based on the theory of Extenics, a new risk evaluation model for large - span tunnel was established. Moreover, the index weights of evaluation were determined using correlation function method. The errors of traditional evaluation method due to subjective factors in the process to determine the weights are avoided by using this new model. And by the use of hierarchy - extension theory to large - span tunnel collapse risk evaluation, the accuracy and reliability of analysis are all improved. This method was successfully applied to the practical risk assessment of Shirenzigou Tunnel. It was use...
