Experimental and numerical investigation on overbreak control considering the influence of initial support in tunnels

被引:22
作者
Chen, Jihui [1 ]
Qiu, Wenge [1 ]
Zhao, Xuwei [1 ]
Rai, Partab [1 ]
Ai, Xufeng [1 ]
Wang, Hailiang [2 ]
机构
[1] Southwest Jiaotong Univ, Sch Civil Engn, Key Lab Transportat Tunnel Engn, Minist Educ, Chengdu 610031, Peoples R China
[2] Shandong Univ Sci & Technol, State Key Lab Min Disaster Prevent & Control Cofo, Minist Sci & Technol, Qingdao 266590, Peoples R China
基金
中国国家自然科学基金;
关键词
Overbreak; Underbreak; Initial support; Contour blastholes; Damage; Drilling pattern; ROCK; DAMAGE; MECHANISMS; QUALITY; DESIGN;
D O I
10.1016/j.tust.2021.104017
中图分类号
TU [建筑科学];
学科分类号
0813 ;
摘要
The problems of overbreak and underbreak exist widely in drilling and blasting (D&B) tunnels. The pattern of traditional contour blastholes (TCB) has drawbacks in controlling overbreak and underbreak due to neglecting the impacts of the initial support. Generally, it brings about the large look-out angle causing overbreak in engineering. Therefore, this paper put forward the long and short associate contour blastholes (LSACB) pattern which had been applied in metro tunnels in Qingdao, China. Field tests showed that the LSACB pattern can control overbreak better than the TCB pattern. After that, damage models were built to analyze the proposed pattern. For example, the rock damage evolution in the LSACB pattern was discussed. The effects of the unsupported length, initial support thickness, and the advance per round on this pattern were also studied further. Finally, combining the LSACB pattern and the existing technology, some suggestions were put forward to control the overbreak. This paper provided an excellent reference for similar projects.
引用
收藏
页数:15
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