Analysis Of The Deformation Impact On High Speed Rail Bridges Based On The Underpass Construction Of Earth Pressure Balanced Shield

With the accelerated modernisation of cities and the rapid development of urban rail transit systems,there are more and more cases of metro tunnels underpassing high speed rail There are more and more cases of bridge construction.As the construction of the shield tunnel will cause changes in the stress field of the surrounding soil,it will lead to changes in the stress state of the bridge foundation,which in turn can have an impact on the safety of the bridge structure.Therefore,it is important to carry out research related to the impact of shield construction underneath high speed rail bridges on the bridge structure.This paper makes a further analysis based on a summary of previous on the basis of the previous studies,the shield tunnel construction of Zhengzhou Metro Line 12 from Huzhuang Station to Longzihu West Station is taken as the background.The construction of the shield tunnel between Huzhuang Station and Longzihu West Station of Line 12 of the Zhengzhou Metro is used as the background.The deformation of the soil and the deformation of the adjacent bridge structure due to the construction of the shield tunnel is investigated in depth.This paper has done the following work in the following areas:(1)Through on-site monitoring of the soil and piers during the construction of the shield tunnel under the HSR bridge,it was found that the ground surface would settle during the construction of the shield tunnel and the settlement would be greatest near the tunnel and the piers would settle.(2)For the construction process before the shield tunnel underpasses the high speed railway bridge,a three-dimensional numerical model was established using ABAQUS finite element software to predict the deformation pattern and influence range of the soil layer caused by the shield tunnel construction,and the settlement pattern of the ground surface caused by the construction of the shield tunnel under different line spacing,different boring speed,different excavation surface pressure and different elastic modulus of the grouting layer was analysed,and suitable construction parameters were proposed for this interval.(3)For the section of shield crossing the high speed railway bridge,a three-dimensional refined simulation method was used to analyse the deformation of the high speed railway bridge structure caused by the shield construction,and a comparative model was established to study the deformation law of the bridge structure caused by the shield construction under different pinch angles between the shield tunnel and the bridge bearing platform.The paper verifies the correctness of the numerical simulation method by comparing and analysing the numerical simulation results with the actual field measurement results.(4)On the basis of the previous study,single factor analysis was used to analyse the effect of pile length,pile-tunnel spacing and pile diameter parameters on the working performance of pile foundations when the shield construction was changed,to compare the working performance of friction piles and end-bearing piles,and to analyse the deformation law of pile foundations caused by the construction of shield tunnels underneath the pile foundations.