Prediction And Inlfuence Analysis Of Land Subsidence For East Main Canal

The city land subsidence is an important geological hazards of city constructionprocess. It has the characteristics of cross-bred with sexual, slow variation,cumulative, and irreversible. Excessive settlement, especially the uneven settlementwill cause additional internal force and deformation of the water conveyance tunnel’sstructure. It will be a threat of waterproof union, to bring hidden trouble to the normaluse of the tunnel, even cause unthinkable safety accidents, causing immeasurablelosses and bad social effect.Through collecting and processing the land subsidence history observation dataalong the project east main canal, the paper got the conclusion that the projectmainly influenced by Laiguangying subsidence area and Dongbalizhuang-Djiaotingsubsidence area. These two subsidence area are expanding and in the process ofgradually connected each others. The rate of Laiguangying ground settlement hasbeen increasing. The land subsidence of Dongbalizhuang-Djiaoting ground settlementchanged from quick to slow, and in recent years the trend is fast increase.This paper make the plain of ground settlement for simulation study area,according to Beijing’s engineering geology and hydrogeology conditions establishedgeological model and the boundary conditions, based on the surface water andgroundwater coupling model research groundwater dynamic change regulation, theProcessing Modflow software IBS module to the Beijing plain each aquifer.Forecasts the future flows and ground subsidence along the project in five years.According to the analysis, in the next five years effected by Laiguangying subsidencearea and Dongbalizhuang-Djiaoting subsidence area, the ground along the project willhappen relatively large ground settlement, the largest settlement in five years is about330mm. The biggest difference settlement on the axis of the convey tunnel in next5years will be0.045‰, far less than the control values of convey tunnel axial biggestdifference settlement0.30‰, which get form combining the relevant standards andexperience. According to the Beijing’s plan of future using groundwater resources, thedevelopment of Beijing land subsidence will be under control from some degree in long term. The safety of East Main Canal will not be influenced during the operation.