Analysis Of The Influence Of Shield Tunnelling On Soil And Shear Wall Structure In Lanzhou

With the rapid development of the economy,the construction of the subway is accelerating.In recent years,accidents involving subway construction have also followed,resulting in a large number of casualties and property losses.The inevitable disturbance to the soil in the construction of the subway and the impact on adjacent buildings need further study.Taking the actual project as the background,combined with on-site monitoring,using the finite element analysis method,the following work has been done on the impact of the subway on the soil and buildings:(1)The impact of subway excavation on the soil was analyzed when there is no building.The excavation of the soil and the support of the lining was simulated by the method of the model change.The stiffness reduction method was adopted to simulate the soil stress release before the lining is installed after the soil excavation.equivalent circle zone was employed to simulate the effect of grouting filling the lining and the soil gap.The vertical settlement and horizontal displacement of the soil were obtained,and the parameters study of the aperture and depth of the tunnel were made.As the radius of the tunnel increases,both the vertical and horizontal displacements of the earth’s surface increase,and the depth of the ground has little effect on the surface deformation.At the same time,the contents of on-site monitoring and construction measures related to the research were summarized.The comparison shows that the calculation results are within a reasonable range.(2)A model of the soil and 17-story frame shear wall house were established.the dynamic process of tunnel excavation was simulated step by step using Python language.Three different tunnel apertures,depth,crossing position and crossing angle were selected for parameter study.The displacement of the house is concentrated on the relatively soft frame part of building.Overall,the maximum vertical deformation is on the upper and lower sides of the lining.The parameter study shows that: First,the analysis of different apertures shows that the vertical settlement and horizontal displacement of the building increase with the increase of the tunnel diameter.Second,the analysis of different buried depths shows that as the tunnel passes through,the vertical displacement of the building continues to increase.For the three working conditions analyzed in this paper,the vertical settlement of the building generated by the 25.2m tunnel is less than that of the 20.2m tunnel,but the vertical settlement of the building caused by the 17.5m tunnel is greater than 20.2m tunnel.Third,the analysis of different crossing positions shows that the vertical displacement is concentrated on the frame part with weak vertical stiffness.The horizontal displacements all point to the side that is biased toward the tunnel.Fourth,the analysis of different crossing angles shows that the maximum deformation of the building when the tunnel axis and the axis of the house overlap in the horizontal plane.The shield structure is twisted when the tunnel is worn at 45 degrees.