Study On The Influence Law Of Large Span Tunnel Construction On The Adjacent Sensitive Structures

At present,the development of underground space is of great significance to the expansion of urban accommodation space,the improvement of land utilization and the alleviation of traffic pressure.However,with the development and utilization of underground space more and more,a variety of underground pipe networks and subway tunnels crisscross each other;at the same time,in order to improve the land utilization rate,the ground buildings gradually become higher and more crowded.Therefore,there are more and more technical problems in the development of underground space.From the point of view of stress and deformation,the excavation of tunnel will cause the stress redistribution of surrounding rock,which will cause deformation of surrounding rock.If the deformation is too large,it is easy to have adverse effects on the existing facilities around,and even cause uneven settlement of the surface buildings,which may lead to accidents such as inclination and collapse.Therefore,how to build a new tunnel in the limited space and ensure that it has a small impact on the existing buildings on the surface and the existing tunnels nearby has become an urgent problem.In this paper,combined with the related engineering practice,the method of theoretical analysis,numerical simulation analysis and measured data feedback analysis is used to analyze the influence law of the new tunnel on the deformation of existing buildings under the ground and the subway station near the upper span under the factors of buried depth,horizontal position and excavation method.The results show that:(1)The buried depth,horizontal position and excavation method of the new tunnel will have great influence on the deformation of the surrounding sensitive facilities;(2)The empirical formula modified by monitoring data is applicable to the project;(3)The results show that the surface settlement and the arch deformation of the new tunnel first decrease and then increase with the increase of the buried depth,and the deformation of the subway station increases gradually with the increase of the buried depth and the reduction of the tunnel spacing;(4)When the new tunnel is symmetrically located above the subway station,the comprehensive deformation of the facilities is small;(5)The smaller the single excavation area of mechanical excavation,the easier to control the deformation of surrounding sensitive facilities;(6)The results of field monitoring and field test are basically consistent with the numerical simulation results,which indicates that the monitoring data and simulation results have certain reliability,and further verify the applicability of the above laws to the project.