Prediction of over-under excavation and optimization of blasting parameters in small section diversion tunnels based on GSI classification

被引：0

作者：

Luo, Yubo ^{[1
]}

Yang, Junsheng ^{[1
]}

Zhan, Shuangqiao ^{[2
]}

Zhang, Qingbin ^{[3
]}

Chen, Yuncai ^{[2
]}

Zhang, Cong ^{[4
]}

机构：

[1] School of Civil Engineering, Central South University, Hunan, Changsha,410075, China

[2] Hunan Water Resources and Hydropower Survey，Design, Planning and Research Co.，Ltd., Hunan, Changsha,410007, China

[3] School of Civil Engineering, Changsha University of Science and Technology, Hunan, Changsha,410001, China

[4] School of Civil Engineering, Central South University of Forestry and Technology, Hunan, Changsha,410004, China

来源：

Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | / 43卷 / 12期

关键词：

Tunneling (excavation) - Well spacing;

D O I：

10.13722/j.cnki.jrme.2024.0402

中图分类号：

学科分类号：

摘要：

To address the challenge of excessive over-under excavation often encountered in the excavation of small-section diversion tunnels due to frequent changes in rock grades，this research investigates quantitative damage prediction and the optimization of blasting effects. The Quanmutang Diversion Tunnel Project was chosen as the case study. Utilizing three-dimensional image reconstruction technology，a relationship between over-under excavation and GSI classification was established. A numerical model was constructed based on actual blasting hole positions，and the mechanical parameters of the surrounding rock，which change continuously，were calculated in the numerical simulation based on a quantified GSI classification method and the Hoek-Brown criterion. Blasting damage was then simulated，and the results were compared with actual over-under excavation for analysis. Subsequently，based on this method，over-under excavation was predicted，and blasting parameters were optimized. The results show that the simulated contour of blasting damage closely matches the actual excavation contour，with an average error of only 2.54% for the simulated over-excavation volume per meter and 5.20% for the field-measured over-excavation volume and shotcrete amount per meter. After predicting rock mass damage under various peripheral hole spacings，blasting parameters were optimized，resulting in no under-excavation and over-excavation was controlled within the design allowable range. By correlating the GSI value with the BQ value，the mechanical parameter ranges for surrounding rock grades II to V are calculated. Over-under excavation for each rock grade under different peripheral hole spacings is predicted，resulting in recommended peripheral hole spacings of 55 cm for grade II–III and 50 cm for grade IV–V surrounding rocks. © 2024 Academia Sinica. All rights reserved.

引用

页码：3032 / 3043