Study On The Estimation Of Waterinflow And Waterburst In Niba Amountaxiangling Tunnel And Fault Of Yaan-Lugu Highway

As a kind of underground lineament building, the tunnel inevitably will pass through different hydrology geology in construction process. Waterinflow is a common geological disaster and the main inducement cause of other geological disasters.it will cause percolating water, emerge flooding ,inrush putty and other disasters in tunnel excavation. The consequence of tunnel disaster is serious,so it is significant of estimating on the waterinflow amount of the tunnel project.Based on the geological analysis principle and the hydrological geology analysis principle, the thesis apply the engineering geology, hydrological geology and numerical simulation theories and measures to the study of the Niba mountain tunnel of YAAN-LUGU highway,and forecast the waterinflow amount of the tunnel and fault.In the course of studying,the thesis draws some conclusions:1.Through on-site investigation and data-collected,the tunnel locates in Sichuan basin subtropical monsoon climate and the qinghai-tibet plateau continental dry climate. The abundant precipitation provide sufficient condition for the water-gushing in the tunnel. There is 16 faults in the tunnel zone,so it is the favorable condition for the existence of groundwater in the tunnel zone by the fracture,which grow in the faults.2.By analysis of the hydrological geology structural features and groundwater types in the tunnel zone,it indicates that the structral fracture zone is the main hydrous body,the intact lava segment is the main water-proof body; the groundwater types are mainly constituted by Q₄ loose rock fissure water, fissure water and carbonatite karst fissure water. Fissure water is the main source of waterinflow in the tunnel,it mainly exists in the fault and fractured area.3.The theoretical calculation of the Niba mountain tunnel waterinflow amount is calculated by atmospheric precipitation infiltration method, groundwater runoff module method and groundwater dynanmics method,.the result indicates that the maximum waterinflow amount of the tunnel is between 29000 to 38000m³/d,the normal waterinflow amount is between 21500 to 25000m³/d.4.The waterinflow amount of the Niba mountain tunnel is computed simulativily by using 3D-FLOW numerical software, and then we analyse the waterinflow amount of the whole tunnel and fractures under the different simulated conditions. The waterinflow amount of the whole tunnel 21383～41366m³/d.we speculate,it is possible to occur the wateburst accident in the main fault of the tunnel ,we should take measures to prevent water-gushing in advance when we work in the fractured zone.