Study On The Effect Of Main Parameters Of Soft Soil Shield Tunnel Construction Change Caused Land Subsidence Major:Architecture And Civil Enginnerring

Guangzhou as one of the fastest growing cities,domestic subway in Guangzhou metro line 4 south section of Guanglong bid to heavy swell as the research object,research mainly in construction of soft soil shield tunneling parameters changes caused by surface subsidence.Shield crossing strata are mainly in the land and sea silt layer,silt soil,how to control the surface settlement of shield tunneling parameters reduce is very important.Bid in this paper,the key location parameter combination analysis,combined with the actual control measures,and to optimize the design of the composite.The main research contents are as follows:(1)This dissertation comprehensive thixotropy,high compressibility and non-uniformity,these soil properties of the mud and silt soil,refer to the domestic and foreign research literature,shield tunneling parameters calculated,draw a parameter value scope,which provides the theoretical foundation for subsequent calculations.(2)This paper Wei Gang professor put forward formula of three-dimensional movement of soil parameters is derived and the clearance formula of ground surface settlement caused by construction technology change and then compared with the actual monitoring data analysis of soil cabin pressure,grouting pressure,total thrust change law of the ground settlement caused by the change.Formula calculation results show that the settlement of change rule and the measured settlement regularity of monitoring are basically identical.(3)With the orthogonal experiment design and working condition of the finite element,the use of Midas GTX numerical simulation analysis was carried out on the test section.The numerical simulation results are intuitive analysis and variance analysis,get three significant parameter to control the surface subsidence.Intuitive analysis and variance significant results: soil tank pressure>propulsion> total thrust of the grouting pressure,the optimal combination for combination with the engineering practice,the tank pressure 0.24 MPa,grouting pressure is 0.2 MPa,shield thrust 13000 kN.(4)Shield through the actual project to solve the problem of the large amount of surface subsidence in the construction,supporting the applicability of the conclusion of numerical simulation;Practical engineering are keep excavation face stability,reduce the disturbance on the surrounding soil,reasonable fill gaps,etc.As the basis of changing the parameters of driving.