浅埋超大断面隧道爆破施工引起的支护结构振动监测分析

Monitoring and analysis of support structure vibration caused by blasting construction of shallow buried super large section tunnel

浅埋超大断面隧道爆破施工时引起的洞内支护结构振动必须严格控制在规范容许范围内.以柳州市柳东新区某隧道项目先行洞爆破施工为背景,对洞内不同掌子面爆破施工时引起的洞内主要支护结构振动进行监测及理论分析.研究表明:双侧壁导坑法施工时,洞内初期支护部位振速远大于二衬砌施作完毕后的复合式衬砌部位振速;结合现场情况分别采用萨道夫斯基公式和日本化药株式会社公式分析了爆破施工时初期支护振动规律,发现日本化药株式会社公式更为适合当前项目;同时考虑高程效应,对公式进行了修正对比后认为,隧道内部爆破施工时,内部支护结构的振速分析和预测可以忽略高程的影响.

The vibration of the supporting structure in the tunnel caused by blasting construction of shallow buried super large section tunnel must be strictly controlled within the allowable range of the specification.Based on the blasting construction of the first tunnel in a road tunnel project,LiuDong new area,Liuzhou City,the vibration of main supporting structures in the tunnel,caused by blasting construction in different face of the tunnel,is monitored and theoretically analyzed.The results show that when the double side wall heading method is used in construction,the vibration velocity of the initial support part in the tunnel is much higher than that of the composite lining after the secondary lining is completed.Based on the field conditions,the vibration law of the initial support is analyzed by using the Sadolfsky formula and the Japanese Huawa Co.,Ltd.formula respectively.It is found that the latter is more suitable for the current project.Considering the elevation effect,the paper has corrected and compared the formula.It is concluded that the influence of elevation can be ignored in the analysis and prediction of the vibration velocity of the internal support structure during the tunnel internal blasting construction.