Ensuring the stability of the tunnel face is crucial for the safety of shield tunnel construction. To assess tunnel face stability during cutterhead operation, we implemented an experimental system incorporating the cutterhead. This system was then utilized to investigate the failure modes of excavation faces in sandy soil layers and the variation in support pressure. Nine sets of physical model tests were conducted using a 1/2 cross-section tunnel model with varying cutterhead states, rotation speeds, and opening ratios to investigate face stability under both static and dynamic conditions. Experimental results indicate that the rotating cutterhead significantly promotes soil movement, leading to higher limit support pressure. Specifically, the limit support pressure is highest when the cutterhead rotates, lowest when stationary, and intermediate when the cutterhead is removed. Neglecting the active rotation of the cutterhead during shield machine advancement could lead to an overestimation of face stability. In addition, elevating the opening ratio and rotation speed of the cutterhead results in an increase in the limit support pressure. Therefore, employing a lower rotation speed and smaller opening ratio for the cutterhead could enhance tunnel face stability.

中文翻译：

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砂土动力刀盘作用下盾构隧道掌面稳定性试验研究


确保隧道掌子面的稳定性对于盾构隧道施工的安全至关重要。为了评估刀盘作业期间的掌子面稳定性，我们实施了一个包含刀盘的实验系统。然后利用该系统研究沙质土层中开挖面的破坏模式和支护压力的变化。使用具有不同刀盘状态、转速和张开率的 1/2 横截面隧道模型进行了 9 组物理模型测试，以研究静态和动态条件下的工作面稳定性。实验结果表明，旋转刀盘显著促进了土体运动，导致更高的极限支护压力。具体来说，当刀盘旋转时，极限支护压力最高，静止时最低，当刀盘移除时，极限支护压力处于中间。在盾构机推进过程中忽视刀盘的主动旋转可能会导致对工作面稳定性的高估。此外，提高刀盘的张开比和转速会导致极限支座压力增加。因此，采用较低的转速和较小的刀盘张开率可以提高掌子面的稳定性。