Study On Deformation Influence & Control Of Up Crossing Engineering Acting On The Existed Metro Tunnel Structure

Along with the abundant construction of city metro and other municipal underground engineering, engineering issue that a new tunnel constructed crossing the existed metro increases gradually. New tunnel construction inevitably disturbed the surrounding strata; thereby it may make additional internal force and deformation on the adjacent metro tunnel. In order to ensure the metro tunnel operated normally and safely, it is necessary to research the mechanism and characteristics of the function that the up crossing engineering acts on the metro tunnel, and establish corresponding control request and measures.By theories analysis, this paper studied the function mechanism of up crossing the existed metro tunnel, expatiated deformation mechanism of the existed metro tunnel and importance of the interlayer soil; Through the establishment of a finite element model, it calculated and analyzed 6 kinds of work condition in up crossing engineering, then the characteristics and regulation were expatiated and the effect of factors such as excavation footage was concluded; Based on aware of function mechanism of up crossing engineering and deformation characteristics of the existed metro tunnel, the paper made analysis and studied on the control criterion of deformation of the metro tunnel structure. The method and process of the criterion establishment were put forward, and corresponding control measures were instituted. With the up crossing engineering case of Gongzhufen in Beijing, calculation result was carried on verification and application.The main conclusions in this paper were list as follows:1) In up crossing engineering, interlayer soil should have a reasonable thickness" H" to make the existed metro tunnel wear a superior load composed of dynamic load and steady load.2) Excavation footage has importance influence on deformation of the down existed metro tunnel. When the tunnel structure transform has a strict request, it should be careful to dig carried with ultra short shoulder and small excavation footage in flabby geologic strata.3) Compared with no movement joints, linear settlement of the existed metro tunnel with movement joints has more rigid characteristics.4) For up crossing engineering, soleplate setup may reduce upheaval of the existed tunnel.5) Since the order getting into soil body settler is dissimilar, the existed metro tunnel will have a transverse deformation. The transect crosses forward the advanced direction of construction.6) Control criterion of the existed tunnel structure deformation will alter with different deformation distribution.