扩建隧道爆破对既有衬砌的影响及安全判据  

Impact from blasting for tunnel expansion on existed tunnel lining and its safety criterion

作　　者：吴忠仕 陈培帅[1,2] 王伟 赵武胜[4] 袁青 江鸿[1,5] WU Zhongshi;CHEN Peishuai;WANG Wei;ZHAO Wusheng;YUAN Qing;JIANG Hong(CCCC Second Harbour Engineering Company Ltd.,Wuhan 430040,Hubei,China;Shaanxi Provincial Major Laboratory for Highway Bridge&Tunnel,Chang’an University,Xi’an 710064,Shaanxi,China;Research and Development Center of Transport Industry of Intelligent Manufacturing Technologies of Transport Infrastructure,Wuhan 430040,Hubei,China;Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan 430071,Hubei,China;Key Laboratory of Large-span Bridge Construction Technology,Ministry of Communications,Wuhan 430040,Hubei,China)

机构地区：[1]中交第二航务工程局有限公司,湖北武汉430040 [2]长安大学陕西省公路桥梁与隧道重点实验室,陕西西安710064 [3]交通运输行业交通基础设施智能制造技术研发中心,湖北武汉430040 [4]中国科学院武汉岩土力学研究所,湖北武汉430071 [5]长大桥梁建设施工技术交通行业重点实验室,湖北武汉430040

出　　处：《水利水电技术》2020年第5期77-85,共9页Water Resources and Hydropower Engineering

基　　金：国家重点基础研究发展计划(973)项目(2015CB057906)。

摘　　要：为了研究扩建隧道爆破振动对邻近既有隧道衬砌的影响,提出合理的安全判据,以二庄科隧道扩建工程为依托,采用现场测试与三维数值模拟相结合的方法,对近距离既有衬砌在爆破荷载作用下的振速峰值和应力进行分析。结果表明:距离爆破开挖面约1.5 b范围内(b为建筑限界宽),既有衬砌的爆破振动衰减速率较快,然后逐渐趋于平缓,两侧基本呈对称分布规律;而距离爆破源最近的既有衬砌迎爆侧边墙振速峰值最大约为背爆侧的5.6倍,上拱部和仰拱其次,背爆侧边墙最小,因此迎爆侧更容易发生破坏。数值模拟与现场测试结果具有很好的一致性,也验证了现场测试结果的准确性和数值模拟的合理性。同时建立了基于振速峰值和最大拉应力的安全准则,得出既有衬砌安全振速判据为10.73 cm/s,从而确定单段最大允许装药量应控制在41.05 kg以内,保证了既有隧道的运营安全。In order to study the impact from blasting vibration for tunnel expansion on the adjacent existed tunnel lining and put a reasonable safety criterion forward,the peak value of the vibration velocity and stress of the close-ranged existed lining under the effect of blasting load are analyzed based on Erzhuangke Tunnel Expansion Project through the method of combining the in situ testing with 3-D numerical simulation.The result shows that the blasting vibration attenuation rate of the existed tunnel lining within a distance of 1.5 b(b:construction clearance width)to the blasting working face is faster and then gradually tends to smooth with the law of the symmetrical distributions on both the sides basically,while the maximum peak vibration velocity at the blasting-facing side wall of the existed lining within a nearest distance to the blasting source is about 5.6 times of that at the back side of blasting,which is then followed by the upper arch and the inverted arch with the minimum at the side wall of the back side of blasting.Therefore,the blasting-facing side is more prone to be damaged.Not only the results of both the numerical simulation and the in situ testing are better coincided,but both the accuracy of the in situ testing and the reasonability of the numerical si-mulation are also verified.Meanwhile,a safety criterion based on the peak vibration velocity and the maximum tensile stress is established,from which the criterion of safe vibration velocity for the existed tunnel lining is 10.73 cm/s,thus it is determined that the maximum allowable explosive charge for a single section is necessary to be controlled within 41.05 kg,so as to ensure the safe operation of the existed tunnel.

关 键 词：扩建隧道 安全判据 爆破振速 现场测试 数值模拟 既有衬砌 

分 类 号：U455.6[建筑科学—桥梁与隧道工程]