Analysis Of Ground Surface Settlement Caused By Shield Tunneling

As the main construction method of subway construction.t Because the subway tunnel often passes through the densely populated buildings in the city,the infrastructure is perfect,the underground pipelines are concentrated,and the traffic is busy.The ground subsidence caused by the shield tunneling has been greatly influenced by the subway design.And builders are concerned.Therefore,it is of great practical significance to study the law of surface subsidence caused by shield propulsion.Based on the tunnel project of Haifu 3#Fengjing^Fuzhou Road Station of Chengdu Metro Line 18,this paper combines the theoretical analysis,measured data and numerical simulation to study the surface subsidence caused by shield propulsion.Analysis and research,the main research work is as follows:?1?The domestic and foreign scholars'research status on surface subsidence caused by shield propulsion,the overall situation of interval tunnel engineering,the interval tunnel monitoring scheme and the theory of surface subsidence caused by the existing shield propulsion are summarized.?2?Using the original 9.0 software to carry out regression analysis on some measured data of the left-line tunnel?first tunnel?,and obtain S_max and D,and then perform dimensionless regression analysis on S_max/D and Z₀/D,and perform regression analysis on i and Z₀.Obtain an empirical formula for the settlement of the cross-section of the ground surface suitable for predicting the left-line tunnel in this interval.?3?Under the premise of not considering the mutual influence of the two-line tunnels,based on the empirical formula of the settlement of the cross-section of the left-line tunnel,the empirical formula suitable for predicting the settlement of the cross-section of the two-lane tunnel is obtained.A typical section is selected in each of the non-crossing artificial lake sections and the artificial lake section.Based on the measured data and the empirical formula of surface settlement,the surface settlement laws of horizontal and vertical sections are compared and analyzed.?4?Using FLAC^3D software to establish a three-dimensional numerical model close to the actual project for the two typical sections selected in the previous section,where:for the non-crossing artificial lake section,based on the stress cloud map and the displacement cloud map,the horizontal and vertical section settlement of the ground surface is carried out.At the same time,the surface settlement is compared and analyzed from different aspects of propulsion and different propulsion sections.For the crossing of artificial lake section,based on displacement cloud map,the horizontal and vertical section settlement of the ground surface is analyzed,and the adhesion affecting surface settlement is analyzed.Sensitivity analysis was carried out with five parameters of cohesion,internal friction angle,deformation modulus,axial depth and axial spacing.?5?In the non-crossing artificial lake section/crossing artificial lake section,through the measured data,numerical calculation results and empirical formulas,the ground settlement law caused by shield propulsion is compared and analyzed,which provides reference for the design and construction of similar projects in Chengdu area in the future.