doi:10.16186/j.cnki.1673-9787.2023090052

Received:2023-09-22

Revised:2023-11-03

Online Date:2023-11-30

Study on the law of water inrush disaster in overlying karst tunnel under damage-seepage coupling（Online）

LIN Zhibin1, LI Yahao1, LIN Peizhong2, ZHANG Boyang1, YANG Dafang1

1.School of Civil Engineering， Henan Polytechnic University， Jiaozuo  454000， Henan， China；2.Henan Natural Resources Monitoring and Land Consolidation Institute， Zhengzhou  450016，Henan， China

Abstract:In order to study the temporal and spatial evolution law of water inrush disaster in overlying karst tunnel， taking Shuangbei tunnel engineering as the background， the rock mass damage-seepage coupling model is established based on the trilinear strain softening model. FLAC3D is used to simulate the deformation， plastic zone， permeability coefficient and water inflow of surrounding rock during tunnel excavation through overlying karst cave. On this basis， the influence of rock mass damage-seepage coupling and different karst cave water pressures on the characteristics of water inrush disaster in the overlying karst tunnel are compared and analyzed. The results show that： （1） After the tunnel excavation passes through the overlying karst cave， the tunnel surrounding rock will produce two 'eight-shaped' water-conducting fracture zones between karst cave and tunnel， resulting in the overall sliding of the rock mass between karst cave and tunnel along these two fracture zones to the tunnel， and serious water and mud inrush accidents occur. （2） In the process of tunnel excavation through the overlying karst cave， the water inrush shows a certain lag， sudden and large-scale characteristics. （3） Compared with the analysis of plastic zone， it is more intuitive and appropriate to study the change of surrounding rock permeability coefficient to reflect the change of seepage or fracture channel between tunnel and water-bearing disaster-causing structure. In order to simulate and reproduce the spatial and temporal evolution process of water inrush disaster in the process of karst tunnel excavation, the damage-seepage coupling effect of rock mass must be considered. (4)In the process of tunnel excavation through the karst cave, the greater the water pressure of overlying karst cave,the earlier the tunnel will start water inrush, and the higher the final water inrush will be.

Key words:karst cave;tunnel;damage-seepage coupling;water inrush;permeability coefficient;water inflow

CLC：U456.33