Study On Face Stability And Drainage And Waterproof System Of Tunnel In Water-rich Strata

With the rapid development of china’s national economy,the cities in the mountains have also achieved unprecedented development.The existing winding mountain roads transportation network has been unable to meet the increasing traffic demand of cities in the mountains.In recent years,highways and high-speed railways dominated by bridges and tunnels can significantly shorten travel time.However,the geological environment in the mountainous areas is changeable,and the construction is difficult and the risk of geological disasters is high.Among them,the safety problem of tunnels in water-rich areas is particularly prominent.The purpose of this paper is to explore the stability of tunnels crossing the fault plane in the water-rich area during the construction phase,and to presenting the stability control measures of the tunnel face.In order to prevent the occurrence of diseases in the tunnel invert during operation,a new waterproof and drainage network system is proposed to ensure the safety and reliability of the tunnel during operation.Based on the principle of fluid-solid coupling,flac3 d software is used to establish a finite difference model.Taking the Dufu tunnel in guizhou province as the research background,systematic study on the construction of mountain tunnel crossing faults in rich water areas and waterproof and drainage network system,the results are as follows:1.combined with the regional hydrogeology and construction data of the Dufu tunnel,hydrogeological models ared established using visual-modeflow software.Through a hydrological year-stability flow simulation of the study area,the model was tested to verify the correctness of the model.The groundwater seepage field in the tunnel area was simulated by using the validated model to evaluate the groundwater environment recovery in the surrounding areas after the tunnel operation and to preliminarily evaluate the stability of the tunnel face by predicting the amount of water;2.the process of the instability of tunnel was simulated,and a method to evaluate the stability of the tunnel face was proposed to determine the extreme thickness of the rock in different working conditions.A high drainage model was established to study the pressure relief capacity to the excavation area of drainage pipes in different positions and quantities.3.According to the geological conditions and design data of the Dufu tunnel,the effects of different circumferential blind pipe spacing on the seepage field under different water level conditions were studied.The average pressure relief capacity coefficient was introduced to evaluate the degree of influence of external factors(water level)and internal factors(blank pipe spacing)on the pressure relief capacity of water-prevention and drainage systems.4.The stress characteristics of the new and traditional drainage network structures are compared and analyzed through elastic beams and bending-curvature beams.The overall force of the new structure is relatively small,which slows down the internal maximum force at the foot of the wall.The deformation of new structure is smaller than traditional structure,especially the uplift displacement of the inverted arch.