Surrounding rock quality evaluation and application development for highway tunnel based on engineering applicability

The stability of surrounding rock is one of the most important problems in the design and construction of a highway tunnel. In this study, the multi-dimensional classification of surrounding rock quality was realized by using the mathematical relationship among surrounding rock classification methods. Based on BQ and RMi systems, the evaluation results of GSI, Q, and RMR systems can be also obtained, which can greatly save decision time and cost for engineering practice. A new surrounding rock risk assessment model considering seven indicators was built by using the analytic hierarchy process, entropy weight method, game theory, and extension theory. The new model was applied successfully in the Beigushan tunnel, and the assessment results obtained by the new model basically agree well with those obtained from field method. In order to facilitate the use of engineering builders, the application called Highway Tunnel Surrounding Rock Classification and Risk Assessment System was developed, thus finally achieving an accurate and rapid quality evaluation of surrounding rock for highway tunnel.