水平岩层特长隧道的爆破参数优化与超欠挖控制

Optimization and Over-break Controlling of Smooth Blasting Parameters of Tunnel in Horizontal Layered Rockmass

为了研究水平岩层隧道中光面爆破的效果,以太古高速S2标的西山特长公路隧道工程(左线)为依托,采用施工现场调查、现场爆破漏斗试验的方法,对水平岩层隧道中超欠挖原因进行分析,从而对爆破的设计参数进行了优化。并应用减小周边眼间距、降低周边眼装药量、采用间隔装药结构、同时加强光面爆破的施工措施,最终使残孔保存率在拱顶处达到50%,边墙达70%;平均线形超挖量小于9 cm,最大线形超挖量为20 cm。现场实际效果证明以上措施有效地控制了光爆超欠挖的不利现象,加快了施工进度,降低了工程造价。

In order to study the effect of blasting in horizontal layered rockmass, based on Xi＇ shan Tunnel on State Road Tai＇ yuan to Gu＇ jiao of the highway $2, this paper, based on research in practical construction site and method of the blas- ting tunnel test, analyzed the reason of excessive and deficient excavation in the tunnel of horizontal layered rock, and opti- mizes the design parameters of blasting. Meanwhile, the technology of reducing the spacing of peripheral hole and the amount of requiring explosive has been employed, and the structure of interval charging explosive and the measure of con- struction management of strengthening smooth blasting have also been put to use. All above produce the final results that the preservation rate of residual holes reaches 50% in the tunnel vault and 70% percent in the side wall, and the height of av- erage linear over-break is less than 9 cm, and the height of maximal linear over-break is 20 cm. Practical experience has proved that these measures successfully controlled the excessive and deficient excavation of smooth blasting, speeded up produ^ion schedule, and reduced cost.