| This project is based on the shield tunnel section from Xinzheng Airport to Zhengzhou South Railway Station.The Anshu finite element software is used as the analysis tool.Firstly,the tunnel structure and the overall structure of the river channel are in the water supply condition and stop.The stress settlement analysis was carried out in the water service repairing conditions,and the safety was verified.After that,the concrete creep constitutive model was introduced,and the stress settlement of the project under 105%ambient relative humidity and75%ambient relative humidity was predicted and analyzed.The safety of long-term operation was discussed.After 10 years,the maximum circumferential compressive stress on the outside of the tunnel lining is 4.61 MPa;the maximum circumferential compressive stress on the inside of the segment is 5.29 MPa.The whole tube is subjected to bending and compression,and its maximum hoop compressive stress is much smaller than the tunnel lining C50 concrete strength design value fc=23.1 MPa.The maximum settlement at the top of the tunnel is 22.16mm,the maximum settlement at the waist is 19.85mm,the maximum settlement at the bottom is17.88mm,and the maximum settlement difference is 4.55mm.Far less than 3‰D=37.2mm.The maximum settlement of the river lining is 13.85mm,which is less than the control standard of 15mm.The maximum settlement difference of the bottom slope of the river slope is 0.45mm,which is much smaller than[S?V]=25mm.The maximum settlement difference at the bottom of the river is 0.23 mm/m,which is much smaller than the allowable settlement difference of 1.087mm/m.The entire structure is safe.According to the comparative analysis,the influence of environmental relative humidity on creep is mainly reflected in the medium-and late-stage stress changes,and has little effect on the settlement changes.When analyzing the stress changes caused by creep,attention should be paid to the influence of environmental relative humidity. |
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