Evaluation of controlled blasting quality for rock-mass tunneling based on multiple indices

Current index factors considered in tunnel blasting quality evaluation are relatively onefold, as well as the unrefined evaluation standards, which may debase the reliability of quality evaluations. In this study, an evaluation index system of tunnel-controlled blasting quality was first established considering the characteristics of geometry and safety. The fractal dimensions of blasting contours were calculated based on the field over/underbreak data using wavelet analysis. Then, the index grades and the index weights were obtained via cluster analyses and an innovative combination weighting method, respectively. Finally, an unascertained measure model (UMM) was established and applied in Zigaojian Tunnel blasting evaluation. The results indicate that the evaluation grade of tunnel blasting quality turns down with the increase of the intensive degree of discontinuities in rock mass. The UMM makes evaluation results more refined compared with the traditional scoring method, which prepares an important basis for the quality optimization of tunnel blasting construction.