Study On The Influence Zone Of Perpendicular Undercross Tunnel Construction On Existing Urban Road

At present,China is in the stage of rapid development of urbanization and industrialization,and the contradiction between supply and demand of construction land is very prominent.Underground rail traffic has become the best way to solve the current urban ground space congestion.Through the urban road engineering,the excavation of the new tunnel will inevitably cause the deformation of the ground surface,which will seriously affect the smooth operation of the road and cause the economic loss.Therefore,it is very necessary to study the influence of the orthogonal tunneling on the stability of existing urban roads.This paper relies on the national key research and development project project-the structural risk monitoring,the key technology of safety control and the demonstration key projects adjacent to the existing urban road in the typical construction project,and combined with the investigation and research,the engineering analogy,the numerical simulation and the theoretical analysis.The relevant research has been carried out in the area.1.Through consulting relevant literature,the influence of the new tunnel on the stability of existing urban road and the law of ground subsidence are studied.The influence factors of the adjacent engineering are determined,the strength parameter of the surrounding rock,the type of tunnel section,the ratio of overlying span,and the load of the vehicle.2.Through the numerical simulation of the initial risk of a single tunnel excavation,the law of the safety coefficient and the displacement of the surface feature points are reduced with the increase of the span ratio.The displacement of the surface feature points is in good agreement with the empirical formula of the Peck.3.Through the calculation of the overall stability of three kinds of train or vehicle under the load of the urban road-freight train,high speed railway and vehicle,the law that the safety coefficient increases first and then decreases with the increase of the span ratio and the increase of the surface settlement with the increase of the span ratio,and the settlement value is greater than the load free condition,and Pe The rules of the CK formula coincide.4.The stability evaluation criteria of the close connection engineering with the safety factor 1 and the ground displacement threshold are proposed,and then the combination curves of various influence factors based on the overlying ratio(H/D)are fitted,and then the distribution characteristics of the affected zones,the influence zones,the influence zones and the shadow zones,are analyzed.The sensitivity of proximity works to various factors is obtained.5.The final influence zone table is applied to similar engineering practice to assist construction.