黄土连拱隧道两主洞开挖面合理间距研究

Study on the reasonable spacing between two tunnels of a multi-arch loess tunnel

山区隧道由于受地形及展线限制,一些较短的隧道常常选用连拱结构型式。通过黄土连拱隧道的三维弹塑性数值模拟,分析了在左洞施工后,右洞施工对左洞的影响规律。对于本工程,黄土连拱隧道的两洞开挖面的合理距离为30 m。推广而言,对于黄土连拱隧道,两洞的开挖距离应为单洞跨度的3倍。

Multi -arch tunnels are often built for driving short tunnels in mountain areas owing to the restriction of geomorphology and route alignment. In this paper, three- dimensional elasto- plastic numerical simulation was carried out for the first multi - arch loess tunnel in China to study the influence of excavation of the right tunnel to the left tunnel which was bored first. It was indicated by the analysis that the reasonable spacing between two main tunnels was thirty meters for this project. In general, the reasonable spacing should be three times of the span of a single tunnel for multi -arch loess tunnels.