深长隧道突涌水灾害防突岩盘模型试验研究

Model test to investigate waterproof-resistant slab for water inrush geohazards in deep buried and long tunnels

为探讨地应力、水压及防突岩盘厚度对掌子面突涌水灾害的影响规律,建立防突岩盘最小安全厚度力学模型,采用相似模型试验方法,开展系列隧道掌子面前方突涌水灾害防突岩盘模型试验。试验成功再现开挖卸荷诱发掌子面前方突涌水灾变全过程,获取不同地应力、防突岩盘厚度组合条件下掌子面突水时的水压力值,分析得出开挖卸荷联合作用下,各因素对突涌水灾害的影响规律。研究表明:随地应力增加,不同防突岩盘厚度下突水时水压展现出相反的变化规律;突水时主要存在沿掌子面中心处的剪切破坏,以及沿掌子面边缘处的渗透突水2种破坏模式,且前者突水时水压明显较后者大。试验结果可为隧道施工期间掌子面前方突涌水灾害风险评估等提供试验基础和数据支撑,也可为类似工程提供参考。

For the sake of investigating the impact rules of strata stress,hydraulic pressure and thickness of waterproof-resistant slab on water inrush,which hazard on the tunnel face,a mechanical model of minimum safe thickness of waterproof-resistant slab for water inrush was established. And a series of pattern tests were carried out by using similar model test method. The experiment smoothly and successfully reproduced the process of sudden water inrush in front of the tunnel face caused by excavation unloading. And the hydraulic pressure value of water inrush was obtained under the condition of different strata stress and thickness of waterproof-resistant slab. The influence law of each factor on water inrush disaster was analyzed under the combined action of excavation unloading. With the increase of the strata stress,the hydraulic pressure during water inrush which under different thickness of waterproof-resistant slab indicates totally opposite change rule. In addition,there were two primary failure patterns for the destruction of the tunnel face for a water inrush disaster. Namely,one was the shear failure occurring at the center of tunnel face. And the other was infiltration failure along the edge of the tunnel face. And the water pressure during water inrush of the former was dramatically higher than that of latter. The test results can provide the trial basis and the data support for the hazard risk assessment of sudden water inrush in front of the tunnel face during the tunnel construction,and can also offer reference for similar projects.