浅埋软岩隧道式锚碇稳定性原位模型试验研究

为了研究高拉拔荷载作用下浅埋软岩(泥岩)隧道式锚碇的稳定性(强度特性、变形规律及长期稳定性),以某在建的长江大桥隧道式锚碇工程为依托,开展了缩尺比例为1∶10的浅埋软岩(泥岩)隧道式锚碇原位模型试验(蠕变试验、极限破坏试验)。研究发现:浅埋软岩(泥岩)隧道式锚碇具有较高的承载能力,在设计荷载甚至在高于设计荷载几倍的荷载作用的情况下,其蠕变变形呈现出基本上趋于稳定的趋势,具有一定的长期稳定性。其破坏模式为锚塞体上方的岩体破裂成块体状,锚塞体下方沿与岩体接触面产生整体错动,破坏的下边界为锚塞体与岩体的接触带,锚塞体混凝土未发生破坏。此外,还探讨了在高拉拔荷载作用下,锚塞体地表围岩蠕变变形的空间分布规律以及锚塞体地表围岩、深部围岩各部位的变形规律。研究成果可为类似的工程提供参考和借鉴。

Stability of shallowly buried soft rock tunnel anchorage by in-situ model tests

To study the stability (strength characteristics, deformation laws and long-term stability) of the shallowly buried soft rock (mudstone) tunnel anchorage under heavy load, based on a Changjiang bridge tunnel anchorage project under construction, the 1:10 reduced-scale models are used for field tests on the shallowly buried soft rock (mudstone) tunnel anchorage. According to the research, the shallowly buried soft rock (mudstone) tunnel anchorage still has the bearing capacity. Under the condition of design load or even several times the design load, the tunnel anchorage also has the long-term stability. The failure mode of the shallowly buried soft rock (mudstone) tunnel anchorage is as follows: the surrounding rock at the upper of the anchorage body breaks into blocks first, then the bottom of the anchorage body slides along the contact surface with the surrounding rock. The bottom boundary of the destroyed area is the contact zone of the anchorage body and the surrounding rock. The anchorage body has no damage. Besides, the spatial distribution laws of the creep deformation of surface surrounding rock and the deformation laws of the surface and deep surrounding rocks are also investigated. The research results may provide reference for the similar projects.