爆炸荷载对不同距离邻近隧洞背爆侧裂纹影响的模拟试验  

Simulation Experiment of Blast Load Impact on the Crack at the Back Side of Adjacent Tunnel with Different Spacings

作　　者：郭东明[1,2] 袁保森 刘康[1] 杨仁树[1,2] 闫鹏洋 

机构地区：[1]中国矿业大学(北京)力学与建筑工程学院,北京100083 [2]深部岩土力学与地下工程国家重点实验室,北京100083

出　　处：《实验力学》2016年第3期369-376,共8页Journal of Experimental Mechanics

基　　金：国家自然基金项目(51274204,51134025);国家重点基础研究发展计划(973)项目(2010CB732002);教育部新世纪优秀人才支持计划(NCET-12-0965)

摘　　要：利用爆炸加载动态焦散线测试系统,模拟了不同起爆距离L时,爆炸荷载作用于邻近隧洞的全过程;通过分析迎爆侧破坏现象和背爆侧预制裂纹扩展的位移、速度以及裂纹尖端动态应力强度因子曲线的变化规律,研究了不同间距并行隧洞爆破开挖对既有隧洞的影响。试验结果表明:随着L增大,隧洞背爆侧裂纹的最终扩展位移呈先增大后减小的变化规律;裂纹扩展速度曲线的振荡幅值以及频率呈降低趋势,Ⅰ型应力强度因子的变化曲线逐渐趋于平缓,且最大峰值均出现延迟现象,最大峰值所对应的时间点由t=50μs^100μs向t>100μs转移;起爆距离L从50mm增大到60mm时,裂纹扩展的位移、速度曲线以及应力强度因子曲线出现显著变化;而小于50mm或大于60mm时,它们分别呈相似性变化。研究结果可为现场试验确定邻近隧洞爆破开挖的距离L提供参考。By using blast loading dynamic caustics test system,the whole process of blast load impact on adjacent tunnel is simulated under the condition of different initiation distances L.Through analysis of the adjacent tunnel damage at the facing blast side and the pre-crack propagation displacement,velocity and the variation of crack tip dynamic stress intensity factor at the back side,the influence of blasting excavation of parallel tunnel with different spacings to the existing tunnel was studied.Experimental results indicate that along with the increase of L,the final extended displacement of the pre-crack at the back side increases first and then decreases;the oscillation amplitude and the frequency of crack growth velocity presents a decreasing trend;the variation curve of typeⅠ dynamic stress intensity factor gradually tends to be gentle,and the maximum peak value was delayed,is transferred fromt=50μs-100μs to t100μs;when initiation distance Lincreases from50 mm to 60 mm,the crack propagation displacement,velocity and stress intensity factor present obvious different variations;but when Lless than 50 mm or larger than 60 mm,their variations are similar to each other.Above results may provide a reference for determination the adjacent tunnel blasting excavation spacing distance L.

关 键 词：爆炸荷载 邻近隧洞 裂纹缺陷 动态应力强度因子 

分 类 号：TD23[矿业工程—矿井建设]