隧道单侧扩建跳槽式开挖方法合理槽宽的确定

随着交通量的日益增加,原有隧道的容量已经不能满足需求,需要在原有的隧道的基础上进行扩建。本文根据隧道扩建的自身特点,建议采用“跳格掏槽,间隔爆破”的扩建方式—跳槽式开挖。从跳槽开挖产生拱效应的机理及力学特性入手,分析了在隧道埋深一定的情况下,通过合理拱轴线模型,得出了隧道扩建跳槽式开挖合理槽宽与预留间隔长度计算公式。结合重庆渝州隧道的扩建工程,确定了该浅埋隧道扩建跳槽开挖的合理掘进长度与预留间隔长度。

The Proper Driving Footage in the Jump-Driving Method for Single-Sided Tunnel Extension

As the traffic volume increased, the original capacity of the tunnel has been unable to meet the needs. So it should be expanded on the basis of the original tunnel. Based on the features of tunnel extension itself, this article suggested an extension way, the ‘jump grid slot cutting, interval blasting’-a hopping type of excavation. Then, it starts from the mechanism and mechanical characteristics of arch effect produced by hopping excavation. Under certain buried depth of the tunnel, through the reasonable arch axis model to establish an equation for calculating reasonable slot width and interval for hopping type of excavation. Based on the extension project of Chongqing Yuzhou tunnel, it has determined the reasonable cycle footage of hopping excavation with shallow buried tunnel extension.