Blasting control technology of horizontal stratified rock tunnel(PDF)
长安大学学报（自然科学版）[ISSN:1006-6977/CN:61-1281/TN]
- Issue:
- 2017年02期
- Page:
- 73-80
- Research Field:
- 桥梁与隧道工程
- Publishing date:
Info
- Title:
- Blasting control technology of horizontal stratified rock tunnel
- Author(s):
- DENG Xiang-hui; CHEN Jian-xun; LUO Yan-bin; LI Xu-dong
- 1. School of Highway, Chang’an University, Xi’an 710064, Shaanxi, China; 2. School of Civil and Architecture Engineering, Xi’an Technological University, Xi’an 710032, Shaanxi, China
- Keywords:
- tunnel engineering; horizontal stratified rock tunnel; blasting parameter; optimization; field test
- PACS:
- U451
- DOI:
- -
- Abstract:
- Due to the influence of horizontal joint and blasting disturbance, separation and slack drop are more prone to occur in arch crown during the excavation of horizontal stratified rock tunnel. At the same time, excessive and insufficient excavation is very common. In this paper, the propagation theory of explosive stress wave was used to analyze the mechanism of horizontal joint under the influence of propagation of stress wave, and the reasons of separation and flat top in tunnel arch crown in horizontal layered rock were explained theoretically. Meanwhile, field blasting parameter optimization tests were conducted to Daliangmao Tunnel. Control measures were proposed to solve the problems of excessive excavation in arch crown and insufficient excavation in sidewall corners of upper steps. The results show that after blasting parameter optimization, the initiation dose of a single shot blasting on the upper steps reduces by 6%, and that of the lower steps reduces by 29%. In terms of blasting effect, the average excessive excavation area of the six test sections reduces from 7.81 m2 to 2.56 m2 after the optimization of blasting solution. The excessive area is only 31% of the original solution and the insufficient excavation can also be controlled effectively. The excessive excavation in the arch crown can be controlled by moving inside periphery holes, appropriately increasing the distance among periphery holes, reducing the amount of charge and taking non-continuous charge. Insufficient excavation of sidewall corners of upper steps can be solved by narrowing periphery holes or adding additional periphery holes. Therefore, the optimized blasting solution can not only greatly reduce the excessive and insufficient excavation of tunnel, reduce the amount of explosives, but also can improve the stability of surrounding rock after excavation, so as to make the tunnel construction safer. The results of this paper can ensure the security of tunnel construction, reduce the excessive and insufficient excavation, save cost and speed up the construction progress. It can provide references for similar projects as well.
Last Update: 2017-04-07