Research On Tunnel Construction Technology Of Intercity Railways Underpassing Existing Integrated Pipe Gallery

In recent years,with the continuous development of urban subways,many difficulties have also been encountered.The construction of new railway tunnels under the existing structure is one of the problems.In this paper,the integrated pipe corridor project of Lingnan Avenue in Foshan City is used as the engineering background.The combination of numerical simulation and on-site monitoring is used to study the deformation of existing integrated pipe gallery,surface settlement and tunnel structure displacement.The law of change.(1)The applicable conditions and applicable scope of the construction method of urban subway tunnel are studied.Combined with the geological conditions of the project,the excavation method selected is shallow buried excavation for the characteristics of large span,small line spacing and shallow depth of the project.The "CRD" method in the law(cross-wall method).In order to ensure that the existing integrated pipe gallery can be used normally,pre-reinforcement measures are taken to reinforce the surrounding soil layer,and the construction plan is determined.The reinforcement measures include: vertical vertical jet grouting pile reinforcement,horizontal jet grouting pile reinforcement,sleeve valve tube grouting reinforcement,large pipe The reinforcement of the shed and the grouting reinforcement of the face are introduced,and the various pre-reinforcement reinforcement principles and construction techniques are introduced.(2)Relying on the Dongping No.1 tunnel,there is a comprehensive pipe corridor project under the Lingnan Avenue,and a three-dimensional numerical model is established.The integrated pipe gallery and the advanced pre-reinforcement area are simulated by the physical unit with changing parameters,and the tunnel undercut excavation is analyzed.The influence of the integrated pipe gallery and the mechanical properties of the tunnel support.The factors affecting the stability of the pipe gallery are analyzed under the condition of the relative distance between different pipes and tunnels and the cross-sectional dimensions of different pipe corridors.(3)The analysis and analysis of the on-site monitoring data shows that the displacements of the pipe corridor,the surface and the tunnel structure are compared with the simulated values.The change laws of the two are generally consistent,and the simulated values are smaller than the measured values,which is due to the complexity of the actual engineering geological conditions.Some simplifications were made during the simulation,such as the simplification of the soil layer,without considering the effects of groundwater.The research results can provide reference for similar projects.