摘要
在小净距隧道开挖工程中,不同爆破施工参数和长距离隧道围岩强度的变化对衬砌结构的稳定性具有重要影响。因此,依托卢氏—洛南高速公路山岭隧道开挖工程,采用ANSYS数值模拟方法和现场振动测试试验,考虑在爆破振动过程中因强烈冲击波和振动作用导致的流固耦合现象,研究了小净距后行洞爆破开挖对先行洞已建支护结构和隧道围岩的影响规律;深入分析了不同围岩等级、不同爆破参数条件下,相邻隧道二衬结构监测点振动速度和爆炸应力传播形式的响应特征和衰减规律。研究结果表明,围岩等级和炸药参数对小净距隧道爆破施工衬砌结构稳定性具有重要影响;后行洞爆破开挖产生的爆炸压力,x、y向振动速度与围岩等级(二~五级)均呈反相关关系;振动速度和压力波出现多个峰值,峰值间隔和首次峰值出现的时间随围岩等级的增大而增加;相对于炸药能量密度,围岩振动速度和压力变化对炸药爆破速度和爆炸压力更敏感。现场监测结果验证了数值计算结果的合理性,该成果可为类似小净距隧道工程爆破施工提供借鉴。
In small internal tunnel excavations,the variations of blasting parameters and the strength of surrounding rock have significantly influence on the stability of the lining structure.Based on the Lushi-Luonan expressway mountain tunnel project,the influence law of blasting excavation of small internal back tunnel on the existing supporting structure and surrounding rock of the tunnel was studied by the ANSYS numerical simulation method and field vibration testing experiments and considering the fluid-structure interaction(FSI)phenomenon induced by strong shock wave and vibration;Under different surrounding rock grades and blasting parameters,the response characteristics and attenuation rules of vibration velocity and explosion stress propagation at monitoring points of adjacent tunnel secondary lining structures were analyzed.The research results indicate that the surrounding rock grades and the parameters of the blasting explosives have a significant impact on the stability of the lining structure in small internal tunnel;The blasting pressure generated by the excavation of the trailing tunnel,as well as the vibration velocities in x and y directions,are inversely correlated with the strength grade of the surrounding rock(gradesⅡtoⅤ);Multiple peaks in vibration velocity and pressure waves are observed.The time of peak interval and the first peak increase with the increase of the grade of surrounding rock;The vibration velocity and pressure changes of the surrounding rock are more sensitive to the detonation velocity and explosion pressure than the explosive energy density.The rationality of numerical calculation results is verified by field monitoring results,which can provide reference for similar small clear distance tunnel blasting construction.
作者
覃宏
朱天宁
王志留
刘运思
Qin Hong;Zhu Tianning;Wang Zhiliu;Liu Yunsi(North China Company of China Communications Road and Bridge Construction Co.,Ltd.,Beijing 101100,China;CCCC First Highway Consultants Co.,Ltd.,Xi’an 710075,China;Zhongyuan University of Technology,Zhengzhou 450007,China;School of Civil Engineering,Hunan University of Science and Technology,Xiangtan 411201,China)
出处
《市政技术》
2025年第3期171-182,共12页
Journal of Municipal Technology
基金
国家自然科学基金项目:温度梯度诱发深部高地温隧道混凝土衬砌早期裂损机理与防控措施(52378396)。
关键词
小净距隧道
LS-DYNA流固耦合
爆破开挖
振动速度
small internal tunnel
LS-DYNA fluid-structure coupling
blasting excavation
vibration velocity
