Research On Tunnel Restrictive Waterproof And Drainage Technology In Fractured Zone Under High Water Level

In the progress of tunnel construction, rich water fracture zone which appears frequently has the characteristics of well fractured, high permeability coefficient and bad self-stability. There are many engineering accidents occurred due to ground water seepage. The main accidents include of water-bursting and mud-bursting, landslide, settlement and so on. The construction schedule, safety and quality are seriously affected which would lead to heavy casualties and significant economic losses. Therefore, it is necessary to study the tunnel construction of the fractured zone in rich water section.Based on the project of “Research on tunnel excavation and restrictive drainage technology in high water level” of Guangdong province Science and Technology Department of Transportation,the research is supported by the No. 1 tunnel of Jieyang Huilai Highway. Combined with the mutual influence of Longtanfeng reservoir and tunnel, the restricted drainage control technology has been researched. It can be concluded as follows:(1) On the reference of domestic and foreign engineering experience of waterproof and drainage, the factors which impact the tunnel waterproof preventing and drainaging have been comprehensive researched. And the actual condition of the project are also taken into consideration. Hence, the allowable discharge Q of the broken section is identified as 3.0m3/(m·d).(2) The type and the side effect of high water level of groundwater in tunnel rupture zone have been studied. The theory of stable flow method and precipitation infiltration method have been used to predict the water inflow in the Xiao Bei Shan tunnel, and the predictive value is 3416 m3/d.(3) The infrared water detector and the geological radar have been used to forecast the water in the broken belt. Exploring the hidden water bearing bodies in front of the face in time, the appropriate measures can be undertaken.(4) The grouting parameters are analyzed, and the various influence factors are explored on tunnel grouting. The optimization of tunnel grouting circle parameters are presented. The permeability coefficient of lining K1 is valued as 9×10-7cm/s. The thickness of grouting circle Tg is valued as 8 m, and the outside diameter of lining r1 is valued as 6.5m.(5) The suitable grouting method and corresponding technology have been studied for the Xiao Bei Shan No.1 tunnel.