第一作者赵振国男，硕士生，1989年生

通信作者卢文波男，博士，教授,博士生导师，1968年生

邮箱：wblu@whu.edu.cn

基于爆破振动影响评价的深埋隧洞围岩二次喷护时期选择

赵振国1,2，杨建华1,2，卢文波1,2，严鹏1,2，陈明1,2

(1. 武汉大学水资源与水电工程科学国家重点实验室，武汉430072； 2.武汉大学水工岩石力学教育部重点实验室，武汉430072)

摘要：二次喷护时期选择是隧洞新奥法施工中的重要课题，而爆破振动对二次喷护结构的影响是选择时需要考虑的重要因素。结合雅砻江锦屏二级水电站4#引水隧洞爆破开挖，采用动力有限元模拟和与现场监测数据对比的综合方法，研究爆炸荷载和开挖面初始应力瞬态卸荷耦合作用下不同龄期喷射混凝土的动力响应。研究结果表明：对于高地应力条件下深埋隧洞爆破开挖，爆破振动作用下混凝土喷层破坏是爆炸荷载和开挖面上初始应力瞬态卸荷耦合作用的结果，喷射混凝土破坏以剪切破坏为主；对于1~3、3~7、7~28天龄期的混凝土喷层，距掌子面安全距离分别是24 m、13 m和9 m。建议锦屏二级引水隧洞二次混凝土喷护施工滞后掌子面6个开挖进尺。

关键词：高地应力；喷射混凝土；爆破振动；开挖卸荷；混凝土龄期

收稿日期：2014-01-08修改稿收到日期：2014-04-16

中图分类号:TU

文献标志码：A

DOI:10.13465/j.cnki.jvs.2015.07.002

Abstract:Choosing appropriate period of time for the construction of permanent shotcrete is a key subject in the New Austrian Tunneling Method (NATM), while the blasting vibration acting on the shotcrete is an important influencing factor. For the blasting excavation of the 4# diversion tunnel in the Jinping-Ⅱ Hydropower Station, dynamic responses of the shotcrete at different ages, induced by the coupling action of blasting load and transient releasing of excavation load, were investigated by the integrated use of numerical simulation and site monitoring. The results show that the shotcrete failure in blasting excavation of deep-buried tunnels is resulted from the coupling action of blasting load and transient releasing of excavation load under high ground stress. The main failure mechanism is the shear failure mode. With regard to the shotcrete at different ages of 1~3 days, 3~7 days and 7~28 days, the safety distance from the tunnel face are 24 m, 13 m and 9 m respectively. The permanent shotcrete is suggested to be constructed 6 excavation footage behind the blasting face.

Selection of spraying time for permanent shotcrete in deep-buried tunnels based on evaluation of the influence of blasting vibration

ZHAOZhen-guo1,2,YANGJian-hua1,2,LUWen-bo1,2，YANPeng1,2，CHENMing1,2(1. State Key Laboratory of Water Resources and Hydropower Engineering Science，Wuhan University，Wuhan 430072，China；2. Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering Ministry of Education，Wuhan University，Wuhan 430072，China)

Key words:high ground stress; shotcrete; blasting vibration; excavation unloading; concrete ages

隧洞新奥法施工中爆破作业与喷射混凝土施工往往交替进行，一次爆破作业完成后，应尽快地完成紧跟工作面的初喷混凝土作业，形成柔性薄层控制围岩变形。爆破振动不可避免会对喷射混凝土结构产生影响。……