某隧道底板大规模突水原因分析与处治技术

某隧道在穿越破碎盐溶角砾岩与完整石膏夹层接触带时，由于充足的地表水源和良好的补给通道，引发隧道底部3 800 m3/h的大规模突水，给周边环境和施工安全造成严重破坏和威胁。如何有效的处治隧道底部如此大的突水，控制施工风险和保证隧道结构稳定成为最关键的技术问题。经过多种方案对比研究，通过“先引后堵、先径向加固再底板封堵、先易后难局部集中处理”的总体步骤，实现了隧道底部突水由快速流动状态到相对静止状态的转变，为隧道底部注浆堵水提供施作条件，再通过径向注浆和深孔底板注浆降低围岩的渗透系数和提高隧道结构稳定性，控制地下水流失，不给通车运营留下质量和安全隐患。

Analysis on Causes of Large-scale Water Gushed from Tunnel Floor and Countermeasures

A large scale water gushed from tunnel floor due to the ample water supply on the ground surface during the construction of a tunnel crossing the contact zone between fracture evaporite solution breccia and complete gypsum layer, which brought serious destructions and threatens to the surrounding environments. As a result, some effective measures have to be took to control water gushing. In this paper, comparison and contrast is made among several grouting methods. With the treating principle of “drainage first and then sealing, radial grouting reinforcement first and then tunnel floor sealing, and centralized treatment of local part”, the water gushing speed is slowed down, the surrounding rock permeability coefficient is reduced, the tunnel structure stability is improved and the ground water is brought under effective control by using radial grouting and deep hole grouting.