Research On Construction Control Technologies Of Shield Tunnel Crossing Buildings In Complex Strata

In urban subway construction,because of the complex urban construction environment,shield tunnel will inevitably pass through all kinds of buildings,which will seriously affect their safe use.In this paper,based on the project background of Fuzhou Metro Line 5 Phase 1 from Chengjin Road Station to Fuzhou South Railway Station,combined with research methods such as data investigation,numerical simulation and engineering measurement analysis,the influence of shield tunnel tunneling under the Fuzhou-Xiamen Railway subgrade,side through the Fuxia Road viaduct pile foundation and under the old houses was studied.The safety construction control technology measures of shield tunnel crossing buildings are constructed.The main research conclusions are as follows:(1)Based on the relevant specifications and practical engineering cases,the deformation control indexes and standards for shield tunnel under passing railway subgrade,viaduct and residential buildings,as well as the common protective measures are summarized.(2)Through numerical simulation,the influence law of shield tunnel construction on railway subgrade deformation and the sensitivity of shield parameters to subgrade deformation are studied,and the construction safety of relying on the project is preliminarily judged;The overall sensitivity is soil elastic modulus > tunnel depth >grouting layer elastic modulus > tunnel net spacing,which provides a basis for adjusting shield construction parameters;Through calculation,the maximum settlement of subgrade is reduced by 17.4%(3)The influence of shield tunnel construction on bridge structure deformation and the influence of different pile tunnel location on single pile deformation are studied by numerical simulation.With the increase of pile tunnel spacing,the influence of tunnel excavation on pile foundation gradually decreases.At the same time,when crossing the pile foundation of different length,it is necessary to avoid the bridge pile foundation in the excavation loose area as far as possible;Through calculation,it can be seen that the displacement of pier can be reduced by 28%.(4)Based on the numerical simulation and the measured data,the influence of shield tunnel construction on the deformation of shallow foundation buildings is studied.By comparing the data,it can be seen that the maximum settlement of the raft foundation of the building is reduced by 53.7% after the micro steel pipe pile grouting isolation is carried out in advance;The maximum settlement of the independent foundation is reduced by 19.4% by grouting reinforcement at the vault of the villager’s house under the bamboo building.