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| Model test to investigate waterproof-resistant slab for water inrush geohazards in deep buried and long tunnels |
| LI Lang，CHEN Xianbo，CHENG Jinxing，LI Miao，YUAN Wei，LI Xiao，LUO Zhongxing |
| (96901 Uint of PLA，Beijing 100094，China) |
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Abstract 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.
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2020, Vol. 39 
