水下盾构隧道双层衬砌分析模型的比较研究

摘要

本文基于荷载结构模型,考虑管片衬砌的接头效应,对比分析了衬砌梁-接头弹簧-结合面梁模型、衬砌梁-接头弹簧-结合面弹簧模型以及衬砌梁-接头弹簧-结合面压杆弹簧组合模型的特点及合理性.由于在结合面和地层接触面径向采用压杆单元模拟,衬砌梁-接头弹簧-结合面压杆弹簧组合模型能有效避免结合面和地层接触面等位置发生径向拉力及结合面切向刚度失真、衬砌弯矩突变等不合理现象,能较准确模拟双层衬砌结构内部之间的相互作用和荷载传递,是目前相对合理的双层衬砌分析模型.应用衬砌梁-接头弹簧-结合面压杆弹簧组合模型探讨双层衬砌的力学行为,研究表明 :特定荷载下,当管片衬砌厚度一定时,增加二次衬砌厚度,双层衬砌的弯矩明显增大,而双层衬砌的轴力变化较小;双层衬砌的弯矩在管片衬砌和二次衬砌之间的分配比例与管片衬砌和二次衬砌的相对厚度无线性关系.上述结论对双层衬砌的设计具有指导意义.%Based on load-structure model,a comparative analysis was conducted on the characteristics and ration-ality of analysis model of lining beam-joint spring-contact surface beam,analysis model of lining beam-joint spring-contact surface spring and analysis model of lining beam-joint spring-contact surface compression bar spring,considering segment joint effect .By the use of compression bar element on contact surfaces,the third model could avoid the occurrence of radial tensile force on contact surface between segment and secondary lining and contact surface between lining and strata,the mutation of bending moment on linings and distortion of ra-dial stiffness on contact surface between segment and secondary lining .With more accurate simulation of the in-teraction and load transmission between the internal structures of double linings,it is relatively a more rational double lining analysis model to date .Conclusions from the study of the mechanical behaviors of double linings with the application of the third model showed that,under the same load and the same segment thickness, when the thickness of secondary linings increased,the bending moment value of double linings increased signifi-cantly,while the change of the axial force value was minor .The distribution proportion of double lining ben-ding moment between the segment lining and the secondary lining had no linear relationship with the thickness of the segment lining and the secondary lining .The above conclusions provide some reference value to the de-sign of double linings in the future .