下卧软弱夹层的软岩隧道式锚碇承载特性研究

Bearing behavior of tunnel anchorage in soft rock with an underlying weak interlayer

为了研究下卧有软弱夹层的软岩隧道锚的承载特性,以拟建的某大桥隧道锚工程为依托,开展缩尺比例为1∶10的隧道锚原位模型试验。通过对模型锚开展荷载试验、蠕变试验和破坏试验等,隧道锚在下卧有软弱夹层的软弱围岩(泥岩)中,是具有一定的承载能力和长期稳定性的。该类隧道锚的拉力向和锚塞体前部的铅直向的地表围岩变形曲线以隧道锚中心轴线为对称轴分别近似呈现出"M"形和"倒V"形,铅直向地表围岩变形从锚塞体前端至后端逐渐减小。对于深部围岩变形,该类隧道锚在拉力向的变形控制应以锚间深部岩体变形为主,在铅直向的变形控制应以锚塞体前部深部围岩变形为主。此外,研究还得出下卧有软弱夹层的软岩隧道锚的破坏模式。研究成果可为类似的隧道锚工程的设计、施工等提供参考和借鉴。

To study the bearing behavior of tunnel anchorage in soft rock with an underlying weak interlayer,a tunnel anchorage model with the size ration of（1∶10） to a bridge？s tunnel anchorage was used for field test. The loading,creeping and failure tests were carried out to the tunnel anchorage model. The tunnel anchorage in soft rock with an underlying weak interlayer has the carrying capacity and the long-term stability according to the research results. The curves of surface settlement of the rock behind the tunnel anchorage show the shape of ＂M＂ and the curves of surface settlement of the rock of the tunnel anchorage show the shape of ＂N＂. The surface settlement of the surrounding rock reduced gradually from the front to the rear of the tunnel anchorage.