隧道二衬结构受力影响因素的敏感性分析

Analysis on Sensitivity of Influencing Factors of Tunnel Secondary Lining Structure Stress

基于荷载-结构模型及有限元分析手段,以200 km时速青荣城际铁路隧道二衬为研究对象,运用敏感系数法对二衬结构受力影响因素的敏感性进行了分析。主要考虑围岩弹性抗力系数、二衬厚度、二衬弹性模量及侧压力系数4个影响因素,并根据实际工程进行取值。分析表明,对拱顶弯矩而言,各因素的敏感性依二衬厚度、围岩弹性抗力系数、侧压力系数及二衬弹性模量而减小;对拱顶轴力而言,各因素的敏感性依侧压力系数、围岩弹性抗力系数、二衬厚度及二衬弹性模量而减小;对拱项竖向位移而言,各因素的敏感性依围岩弹性抗力系数、二衬厚度、侧压力系数及二衬弹性模量而减小;对拱顶截面安全系数而言,各因素的敏感性依围岩弹性抗力系数、侧压力系数、二衬厚度及二衬弹性模量而减小。

Based on load-structure model and FEM, taking the secondary lining of Qingdao-Rongcheng intereity railway tunnel with 200 km/h train speed as research object, the sensitivity analysis of the influencing factors on second lining internal forces is conducted by sensitivity coefficient method. The influencing factors are elastic resistance coefficient of surrounding rock, secondary lining thickness, elastic modulus of secondary lining and lateral pressure coefficient, whose values are taken from the engineering practice. The analysis result shows that （1） to vault bending moment, the descending order of the sensitivities of the influencing factors are secondary lining thickness, elastic resistance coefficient of surrounding rock, lateral pressure coefficient and elastic modulus of secondary lining; （2） to vault axial force, the descending order is lateral pressure coefficient, elastic resistance coefficient of surrounding rock, secondary lining thickness and elastic modulus of secondary lining; （3） to vault vertical displacement, the descending order is elastic resistance coefficient of surrounding rock, secondary lining thickness, lateral pressure coefficient and elastic modulus of secondary lining; （4） to safety factor of vault cross-section, the descending order is elastic resistance coefficient of surrounding rock, lateral pressure coefficient, secondary lining thickness and elastic modulus of secondary lining.