Impact Of Excavation Of Deep Foundation Pit Of Qunan Road Highway Tunnel In Zhengzhou On Surrounding Environment

With the development and utilization of my country’s underground space,many cities have put on the construction of the road tunnel.The construction of the tunnel often has a foundation pit project.The excavation of the deep base pit will change the surrounding soil stress field.Self-stability and a large influence of neighboring underground pipelines.Therefore,it is of great significance to its own stability and the effects of adjacent pipelines.Thi s paper is based on the deep foundation pit project of Zhengzhou Dunan Road Highway Tunnel.Through MIDAS Finite Element Software,the foundation of the foundation pit excavation is simulated.Combined with the on-site measurement law and the influence of adjacent pipelines,and further investigated different buried Deformation and internal force change law of deep,bubble,pipe diameter and material.The main research contents are as follows:(1)Combing domestic and foreign scholars on the excavation of foundation pit projects and the effects of surrounding environment,summarizing concrete foundation pit deformation mechanisms and control standards and protective measures against underground pipelines.And through real-time monitoring of the deep foundation pit project of Dunan Road,the data was obtained.The results show that the surrounding surface of the foundation pit is ultimately presented as a groove type change;the vertical overall deformation trend of the enclosure structure exhibits a "drum" shape in the middle,and the maximum displacement point is gradually moved.Excavation.Near the surface.(2)The multi-process simulation analysis of deep base pit is excavated by MIDAS software,and the results of simulation calculation and on-site monitoring data are compared.The results show that the simulation value of the surface,the enclosure structure,and the deformation of the pipeline and the measured value are basically consistent,and the reliability of the numerical simulation is verified.A fter the pipeline of the foundation pit,the vertical and lateral displacement of the pipeline gradually increases,until the central portion of the foundation pit is increased to the extreme value;the total vertical deformation of the hydrated pipeline c ross the bottom of the base pit.The longitudinal direction of the pipe is a Gaussian distribution form,and the base pit bottom plate is inhibited by the bottom line of the foundation pit.After the opening of the foundation pit excavation,the pour of th e bottom plate should be carried out as soon as possible.(3)Considering four influencing factors such as different buried depth,bubble,material,and pipe diameter,the establishment of the simplified foundation pit-line model by MIDAS software,and it is concluded that the deformation trend of the pipeline and the burial of the pipeline Deep,pipe diameter,bubble,stiffness,in which horizontal displacement deformation is affected by vertical displacement.The pipeline stiffness has the most highlight ed impact on the torque of the pipeline,and the steel tube wire is much longer than the PVC line.