Geo-mechanical model test on the water inrush induced by zonal disintegration of deep tunnel under hydro-mechanical coupling

Abstract

With the increase of burial depth, complex geological environments such as high in-situ stress and high seepage pressure will inevitably affect the generation of zonal disintegration and may induce water inrush disasters during the excavation of the deep tunnel. A true three-dimensional geo-mechanical model test is conducted to study the mechanism of water inrush induced by zonal disintegration under hydro-mechanical coupling. The distribution and variation of different physical information during excavation, including displacement, stress and seepage pressure, are comprehensively analyzed. Test results reveal that zonal disintegration may induce water inrush when the tunnel is excavated under the coupling action of high stress and high seepage pressure. The excavation disturbance causes the stress in the rock mass to be oscillating. As a result, rupture and non-rupture zones appear alternately around the tunnel. With the increase of seepage pressure, the rock mass in non-rupture zone, which acts as the water barrier, is damaged and connects with rupture zone to form a water inrush channel. Eventually, high-pressure water pours into the tunnel to form a water inrush disaster. The reproduction of this special phenomenon will provide an important test basis for further theoretical and numerical studies.