Research On Influencing Factors Of Surface Subsidence And Control Technology In Construction Of New Tubular Roof Method

With economic development,population growth,and the continuous expansion of cities,urban traffic has become increasingly congested.Underground space,with its huge potential,provides realistic possibilities for solving the spatial constraints of urban development.The New Tubular Roof Method is widely used in the construction of underground spaces such as subway tunnels in recent years because of its wide range of applications,many applicable sites,and little impact on the surrounding environment.How to effectively control the settlement and deformation of the ground surface during the construction of the New Tubular Roof Method is the key to measuring the success of the construction of the New Tubular Roof Method important question.This article relies on the project of passing through the railway station under Yingze Street in Taiyuan City,taking full advantage of the excellent research results of the predecessors and related foundations,and adopting a comprehensive research method combining theoretical analysis,numerical simulation,monitoring and measurement,and field test to target In the construction of the New Tubular Roof Method,researches were carried out on the steel pipe jacking speed,steel pipe diameter,steel pipe jacking sequence,and surface settlement control technology.The following conclusions are obtained:(1)From the two aspects of stress state in undisturbed soil layer and stress state in disturbed soil layer,the influence mechanism of the New Tubular Roof Method steel pipe jacking on deformation of overlying soil is studied.By studying the distribution of surface subsidence in the cross section and the longitudinal variation of the surface subsidence,the deformation form of the overlying soil in the pipe curtain section under the condition of steel pipe jacking is obtained,and the surface destruction method is clarified.It has laid a theoretical foundation for further research on the influencing factors of ground settlement in the New Tubular Roof Method.(2)Through the field jacking experiments,the influence of different jacking speeds of steel pipes on soil settlement was analyzed.According to the monitoring results,it is found that the settlement changes after completion of different jacking speeds are different,and the surface settlement within a certain range becomes larger as the jacking speed increases.In the process of jacking up the steel pipe with the New Tubular Roof Method,the shape of the measured lateral settlement curve is basically the same as that of the Peck normal distribution curve.(3)Through theoretical calculations and numerical simulations,the influence of different diameters of steel pipes on soil settlement was analyzed.Through numerical simulation,it can be concluded that different diameters of steel pipes have a certain effect on the surface settlement.With the increase of the diameter of the steel pipe,the surface settlement gradually increases during the jacking of the steel pipe.(4)Combined with the project of crossing the railway station on Yingze Street in Taiyuan City,it is obtained through numerical simulation of ABAQUS software that the different sequences of steel pipe jacking have different degrees of impact on the deformation of the overlying surface soil layer.First,jacking the upper row of steel pipes first,then jacking the lower row,has the greatest impact on the vertical displacement of the overlying surface soil layer,followed by the continuous form of pipe jacking construction.Relying on the project of crossing the railway station on Yingze Avenue in Taiyuan City,the most suitable jacking sequence was determined according to the site conditions of the construction site,which effectively ensured the construction quality and saved time and money.(5)By studying the effects of steel pipe jacking speed,steel pipe diameter,and steel pipe jacking sequence on the settlement deformation of the overlying surface soil during the construction of the New Tubular Roof Method,the research on the New Tubular Roof Method surface settlement control technology is studied,In the previous theory and simulation analysis,it is proposed to select a steel pipe with a diameter of 2000mm for steel pipe jacking,and the steel pipe jacking speed is 75mm/min.Technical control measures such as buckle rail reinforcement,grouting reinforcement and pipe roof reinforcement.Through this research,it can provide theoretical guidance and technical support for the application of the New Tubular Roof Method for surface settlement deformation control engineering.Safety,economy and environmental protection have important social significance.