Abstract: To optimize and control the over/under-excavation phenomena observed in the excavation of flat and super-large cross-section tunnels using the drill and blast method. A highway tunnel served as a case study, where numerical models for tunnel sections with Grade III and IV surrounding rock were established. The blasting process of the tunnel cross-section was replicated, and field-measured data were utilized to validate the numerical models. Analyses were performed on the variations in blast damage nephograms, blast profiles, maximum and average over/under-excavation distances, and over-excavation areas across different blasting schemes. These analyses quantified the impact of varying peripheral and cut hole spacings, as well as the charge quantities in blast holes, on the over/under-excavation during tunnel blasting. Subsequent to these analyses, the blasting schemes were optimized. By integrating numerical simulation outcomes with field-measured data, an optimal construction scheme was deduced that effectively minimizes over-excavation: the peripheral hole spacing was adjusted to 1 m for Grade III surrounding rock and to 0.8 m for Grade IV. The findings of this research offered significant reference value and guidance for the control of over/under-excavation and the optimization of blasting schemes in flat and super-large cross-section tunnels.
田瑞端, 莫冠旺, 李响. 超大断面扁平结构隧道矿山法超欠挖优化控制研究[J]. 隧道与地下工程灾害防治, .
TIAN Ruiduan, MO Guanwang, LI Xiang. Optimization on the over/under-excavation of flat and super-large cross-section tunnel with drill and blast method. Hazard Control in Tunnelling and Underground Engineering, 0, (): 1-.
