Analysis of Abnormal Strut Axial Forces for Narrow and Long Deep Excavation of Metro Stations
[Objective]The purpose of this paper is to address the issue of excessive axial force in the first sup-port of a narrow and long deep excavation of metro stations during construction.[Method]Through the method of finite element analysis using the hardening soil model with small strain stiffness(HSS),the excavation meth-od of the station pit,poor quality of steel support installation,and the untimely stressing of the steel support are simulated in a refined way to analyze the influence on the axial force of the first support.[Result]The results show that the use of basin excavation has a significant effect on the axial force of the first support,which increas-es by 45%compared with the case of layered excavation,and the corresponding position of the steel support should be installed in time;when the prestress of the installed steel support does not reach the design value,it will lead to an increase in the axial force of the top support at the end of the excavation,with an increase of 10%or less,and a decrease in the axial force of the bottom support.[Conclusion]Basin over-excavation should be strictly limited during excavation of narrow and long deep excavation of metro stations;The effect of tempera-ture changes on support axial forces cannot be ignored;when the prestressing force of the installed lower steel support fails to reach the design value,it will lead to a large axial force of the top support at the bottom of excavation.
narrow and long deep excavationstrut axial forcehardening soil model with small strain stiffnessbasin excavation method
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