Study On Mechanical Response Of Dug Station Structure Based On Different Excavation Modes

In the current railway system construction in China,stations are still mainly constructed on the ground.However,under the general trend of increasingly tense urban construction land and the development and utilization of underground space,underground railway station will appear more in people’s lives.Hiding the massive station underground will reduce its impact on the urban environment,save land,and conform to the trend of urban development.However,due to the small number of underground railway station in China and the limited samples available for reference,it is of great value to study how to select the appropriate station structure and what excavation scheme to carry out construction.Based on the project of Huangmaoping Branch National Expo Center of Chongqing Railway Terminal East Ring Line,this paper studies the structural type and excavation scheme of underground railway station by combining theoretical analysis,numerical simulation and field measurement.The main research content and achievements are as follows:(1)The ABAQUS finite element software was used to model and analyze the single arch and double arch structures,and the maximum surface settlement,maximum arch crown settlement,maximum inverted arch uplift,maximum arch waist displacement,maximum displacement at the midpoint of the side wall,and maximum arch foot displacement of the two structures were obtained.The difference between surface settlement and arch crown settlement was significant,and the double arch structure station was 22.2mm and 22.98 mm larger than the single arch structure station,respectively,By comparing the displacement and deformation of two types of station structures horizontally,it is concluded that the single arch structure station is the optimal structure.(2)The ABAQUS finite element software was used to optimize the cross-sectional size of a single arch structure,and the model 2 with a five center circle R1 of 12430 mm was obtained.The surface settlement and arch crown settlement can be reduced by67.4% and 49.8% respectively,which is the optimal structural cross-sectional size.(3)Using ABAQUS finite element software to establish models for different excavation schemes,the improved construction methods were obtained with the maximum settlement values of the surface,the maximum settlement values of the arch crown,the maximum uplift value of the inverted arch,the maximum displacement values of the arch waist,the maximum displacement values of the midpoint of the side wall,and the maximum displacement values of the arch foot,which were-21.78 mm,-27.67 mm,39.27 mm,4.31 mm,-3.11 mm,-3.11 mm,7.24 mm,-7.07 mm,and-3.40 mm,respectively By comparing the displacement generated by the two excavation schemes horizontally at 3.46 mm of the right arch foot,it is concluded that the improved excavation method is the optimal one.