Damage behaviors, prediction methods and prevention methods of rockburst in 13 deep traffic tunnels in China

Abstract

Rockburst seriously threatened construction safety of deep traffic tunnel in high geostress condition. In recent years, a large number of deep traffic tunnels have been constructed in China, some of which occurred many rockburst disasters, especially in Qinghai-Tibet Plateau and Qinling-Daba Mountainous area. In this paper, 13 cases of these two areas were employed to address typical damage behaviors, the key prediction methods and prevention methods of rockburst in deep traffic tunnels. The results indicated that Bayu tunnel, Sangzhuling tunnel, Micangshan tunnel suffered the most serious rockburst, and all 13 traffic tunnels showed different degrees of structural damages, and rockburst was mainly concentrated within a few hours to half day after blasting, and mainly occurred in crown and side walls of cross section of tunnel; rockburst in deep traffic tunnels was mainly manifested in the cracking and collapsing of primary support, deformation and fracturing of steel arch, peeling of bolts and rock mass, cracking and uplifting of inverted arch; multiple index methods were more reliable than single index methods in predicting rockburst in design stage, and the latter was often used with decision analysis methods; MS monitoring method and AE method was the main in-situ monitoring method in predicting rockburst in construction stage, and they were sometimes used with the TBM method; prevention methods of rockburst in traffic tunnels were mainly stress release of rock mass, improvement of construction methods, improvement of support measures, protective measures for construction personnel and equipment.