Impact of Excavation Blasting of the Heihe Connection Tunnel on the Stability of Water Diversion Tunnel
Given the increasing attention to the complex stress state and stability issues at the intersection section be-tween the construction branch tunnel and the main tunnel,a simplified group hole blasting method is proposed,which takes into account the explosive section placement and site-specific differences during blasting.The corresponding dynam-ic load for tunnel excavation blasting is formulated,and a three-dimensional dynamic finite element analysis method is a-dopted to study the impact of blasting vibration from the excavation of the Heihe connection tunnel on the stability of the surrounding rock and the safety of the lining structure of the already built water diversion tunnel during the intersection construction process.The results show that the vibration velocity at the key points of the Heihe water diversion tunnel lining gradually increases as the distance from the blasting load decreases,with the maximum vibration velocity occurring mainly within 17 meters in the direction of the acute angle from the intersection.The lining vibration velocity ranges from 0.733 cm/s to 9.76 cm/s.The blasting attenuation rate is relatively fast,and the location of the blasting point should be considered to reduce unnecessary treatment measures during blasting.According to the specification requirements,only one monitoring point showed a maximum vibration velocity slightly exceeding the minimum standard,and the duration of the exceedance was very short,suggesting that the implementation of eight-phase blasting construction meets the require-ments.
万方数据
维普
