Tunnel Construction On Neighboring Expand The Basis Of The Impact Study Of The Bridge Structure

The development of urban tunnel has resulted in a number of problems about the tunnel across the bridge,the construction of which makes the ground surface displace, and influences the states of the bridge.It is important for assuring the using safely of the bridge and the constructing successfully of the tunnel that the influences of the states of the adjacent bridge structure due to tunnel construction are researched and then measurements are taken effectively in order to decrease the degrees of the influnces.According to the project of Jinshazhou Tunnel across Guangfu Overpass,the influnces of the states of the expanded fundation bridge due to the construction of urban tunnel have been analysed, and the reactions of free beam,continuous beam and the understructure thanks to the displacement and deformation of ground surface have been researched.The main contents of this paper are as follows:1,The mechanism of ground surface settlement due to the construction of the tunnel has been analysed.The Peck and other relevant formulas have been discussed,and value methods of equipollent radius,ground loss and trough width have been chosen.2,The types of bridge damage have been analysed qualitatively, which include the influences from ground surface settlement, horizontal displacement, inclination, curvature and horizontal deformation.3,After the influences of states including support settlement and settlement D-value between the adjacent support of the free beam, bearing ability of right section, bearing ability of oblique section,anti-crack ability of right section, anti-crack ability of oblique section and deflection of the continuous beam and displacement of the bridge pier top,eccentricity of foundation base and stability of foundation base of the understructure were analysed,the system of bridge damage assessment due to tunnel construction has been established.4,After the states of the free beam,the continuous beam and the understructure were analysed with the Midas/Civil, it has been concluded that the anti-crack ability of right section is most hypersensitive to the ground surface settlement,and the displacement of the bridge pier top is most hypersensitive to the ground surface inclination and horizontal displacement.5,After the project about Jinshazhou Tunnel across Guangfu Overpass was analysed, the controling values of ground surface settlement and ground loss have been presented,which offer the reference for construction of Jinshazhou Tunnel.