The Analysis And Research Of Station House And Railway Track Being Crossed By Shield Tunnel

With the acceleration of urbanization, the number of city dwellers is increasing and the relevant urban rail transit construction is booming, and there is growing trend.Shield construction as a kind of construction method for urban rail transit construction has been applied in35large and medium cities nationwide by December2013. In the center of the built-up urban area, using the method will affect the formation within the influence range of construction. When shield tunnel beneath existing railway operating track and station house, it will cause the surface settlement, and the station house foundation stress will be changed. If the influence of shield tunnel on the railway track and station house foundation is too much, it will affect their normal use. Therefore, the research of effects of shield tunneling on existing railway track and station house foundation has important practical significance.In this paper, take the interval between Hengyang West Station and Railway station of a southern urban rail transit line1as the engineering background, in which the tunnel crosses the railway track and station house foundation. Based on engineering geology detail of this part, the shield tunnel crossing the railway track and station house foundation has been studied using numerical simulation method. The main results include:First, through calculation and analysis of strata settlement under the condition that Shield tunneling cross railway track, in which under its own conditions and take appropriate engineering measures conditions. The range of railway roadbed transverse and longitudinal settlement by shield tunneling is summarized: the longitudinal impact range is about65meters, the transverse impact range is about25meters ahead and the rear28meters, the maximum subsidence value of the fields is25.9mm, the settlement difference between adjacent rails is11.13mm. Combined with the corresponding engineering case appropriate measures are taken, which ensure the normal operation of the railway. The second, according to the engineering detailed geological data and using numerical simulation, during shield tunneling cross station house base, regulations of station house pile stress variation and tunnel segments stress variation are summarized: station building pile foundation settlement is about19.8mm,the maximum ground settlement is about22.3meters, in which the maximum differential settlement of pile foundation is about4.5mm,the adjacent pile foundation settlement is about2.6mm,the differential settlement is less than12mm.Each construction stage, segment stress is relatively small, the maximum compressive stress is about2.0Mpa,the maximum tensile stress is about1.0Mpa;bending moment and axial force distribution is affected by construction successively, which is the asymmetric distribution, construction of the tunnel after excavation tunnel segment stress significantly greater than first segment. In the end, according to the results of numerical simulation and refer to the domestic construction project examples, in order to guarantee the quality of shield excavation and reinforcement parameters under the condition of reasonable, ground reinforcement and hole grouting method is used to deal with the soil, which can make the railway track settlement and the station foundation settlement under control. The appropriate measures to reinforce the construction project are determined by measures comparison related to construction. It provides a theoretical basis for the subsequent construction to ensure construction safety.