| The super large diameter slurry balance shield tunnel was mainly used in large river and sea crossing projects.With the development of underground space,urban underground expressways have also begun to adopt this form.Construction of super large diameter slurry balance shield tunnel in densely populated urban areas will inevitably disturb the surrounding strata and cause the building to deform accordingly.If not accurately estimate and take reasonable measures before construction,they will cause adverse effects on buildings.When the tunnel is surrounded by multi-storied buildings,the Buildings will be more vulnerable because the low structural strength and shallow foundation.Therefore,analyzing the influence of the ultra-large diameter mud-water balance shield on the deformation of adjacent multi-storied buildings has a strong practical significance for reasonable construction control.On basis of shield tunnel project of Beiheng Passage in Shanghai,the paper used the methods of analysis of measured data and numerical simulation to analyse and discuss the disturbance of super large diameter slurry balance shield construction to the building and surrounding ground,The main research contents are as follows:(1)On basis of measured data,the paper dicuss the Soil disturbance and ground surface deformation between the whole process of shield excavation,segment erection and grouting.With a relationship between the depth of the tunnel,grouting pressure,grouting continued to settling and then settling to the raised surface deformation of the two feature time history analysis.(2)Analyze the cross section of the lateral settlement tank formed by a large number of measuring points in this project,the results show that they are different from traditional Peck curves and It is more like an M-shaped settlement groove section,which is more suitable for description using the modified Peck formula.The Peck formula can comprehensively reflect the combined effects of formation disturbance and grouting.Using the finite element software Plaxis2D,the effects of shield shrinkage,grouting stratum stress ratio,cover diameter ratio,and soil layer parameters on the main parametersK_l、V_l、K_h、V_hin the modified Peck formula were systematically analyzed.(3)Based on the measured data of the building measurement points and the settlement observation data of the adjacent ground surface,the deformation and development law of the four shallow multi-storied buildings on the eastern line of the Beiheng Tunnel were analyzed during the shield tunneling,inclouding deformation value,deformation rate,gradient and torsion angle.The analysis shows that the buildings directly above the tunnel are liable to settle,and the buildings on both sides of the tunnel are prone to heave;For buildings of the same structure type,the settlement and settlement rate of the building are greater than those of the corresponding side-passing buildings when the tunnel passes through,and the heave rate is lower than that of the side-passing buildings.(4)The finite element software Plaxis 3D was used to select Zhaofeng Villa F to establish a tunnel-soil-building coupling model.Based on the model verification,the different influences of the factors such as coverage ratio,horizontal distance between building and tunnel,the angle between the longitudinal axis of the building and the longitudinal axis of the tunnel,building stiffness and foundation depth,shield cutting pressure and grouting pressure on the deformation of the building during the tunnel crossing are systematically analyzed. |
PDF Full Text Request