Study On The Deformation Mechanism And Deformation Control Technology Of Interval Shield Tunnel Under The Existing Station

In recent years,with the rapid development of socio-economic level and population urbanization,the above-ground structure has not met the needs of human survival.The development of underground engineering is getting more and more attention and challenge.Among them,the research on subway safety construction technology under the complex conditions of silty sand stratum has become the research focus of all countries.This article takes the shield tunnel of Shijiazhuang subway line 6 under the transfer station of Huaian bridge in the line 3 as the actual engineering background.Deformation mechanism and control measures of shield tunnel under-passing project in silty sand stratum are studied.The main research contents are as follows:(1)Research and analysis the theory of the subway shield tunnel under-penetrating engineering on the formation and the adjacent buildings through a large number of reading articles on shield tunneling engineering theory.List the division table of under construction tunnel near degree and it points out the control index value of the relevant parameters of the subway station under the subway station.(2)Using FLAC3 D software to simulate the deformation mechanism of metro station under subway tunnel,the vertical displacement of subway station structure is obtained with the variation of each excavation step.Through optimizing the deformation controlling measures under the wear-through engineering,it proposes four kinds of control deformation technology measures program such as floor thickening,surrounding reinforcement,bench pile reinforcement and sleeve valve pipe grouting with bench pile reinforcement.By the comparative analysis from the aspects of the stress and deformation of the main structure of the station,the main stress of the shield tunnel lining structure and the deformation of the strata,it ultimately obtains the best solution related to sleeve valve pipe grouting with bench pile reinforcement.(3)In order to more specifically analyze the most suitable technology program of deformation control,it can study on the rationality of the design of the fence structure of bench pile under the station structure.Main studies are carried out from the different length of the pile,the longitudinal spacing of piles and pile diameter.With the comparative analysis and research of the station,the shield tunnel lining structure,soil bench stool and other objects,it finds out the reasonable design range of pile length,pile spacing and pile diameter,so that the impact of the construction of subway shield excavation on existing neighboring buildings becomes smaller.