摘要
针对上软下硬岩体大断面隧道掏槽爆破开挖存在掌子面中底部欠挖和超大尺寸块石的问题,依托海螺峪隧道工程背景,应用现场调研和试验的手段,提出了隧道掏槽爆破技术的优化方法。基于掌子面上软下硬的岩体特征,从减小掏槽爆破孔口距和装药集中度的方面,提出了复式楔形掏槽方式、增加掏槽孔数量、减小掏槽孔最大单孔装药量和增设底孔等措施。结果表明:采用优化的掏槽爆破技术,可消除掌子面中底部的欠挖,形成平整的开挖掌子面和底面;大大减小了爆后块石尺寸,最大边长减小60%;炮孔利用率提高3.4%,炸药单耗减小0.03 kg/m3。
In order to solve the problems of underbreak in the bottom of the tunnel face and big block caused of the large cross-section tunnel with upper soft rock and lower hard rock by cutting blasting excavation,based on the Hailuoyu tunnel project,the optimization method of cutting blasting technology was proposed by using the on-site investigation and experiment.Taking into account of reducing the hole spacing and charging concentration of cut blasting,the optimized cutting blasting parameters,such as the duplex wedge cut design,adding cut holes,reducing the maximum single hole charge of the cut hole,and adding bottom holes,were proposed by analyzing the characteristics of the soft and hard rock mass.The results show that the underbreak at the middle and bottom of the tunnel face can be avoided due to the optimized cutting blasting technology,forming a flat excavation face and bottom surface.The block size can be greatly reduced,and its maximum side length is reduced by 60%.The utility of the blasting holes is increased by 3.4% and the powder factor is reduced by 0.03 kg/m^3.
作者
朱永学
王丙坤
谢丰泽
徐帮树
张万志
张剑
蒋勇
ZHU Yong-xue;WANG Bing-kun;XIE Feng-ze;XU Bang-shu;ZHANG Wan-zhi;ZHANG Jian;JIANG Yong(China Railway Tunnel Group No.2 Co Ltd,Langfang 065201,China;Geotechnical and Structural Engineering Research Center,Shandong University,Jinan 250061,China;School of Transportation and Civil Engineering,Shandong Jiaotong University,Jinan 250357,China)
出处
《爆破》
CSCD
北大核心
2020年第4期53-58,共6页
Blasting
基金
国家自然科学基金青年科学基金项目(50909056)
山东省自然科学基金面上项目(ZR2014EEM014)。
关键词
隧道工程
大断面
上软下硬
掏槽爆破
大块石
tunnel engineering
large cross-section
soft to hard rock
cut blasting
big block
