基于壳-弹簧模型大断面盾构隧道管片衬砌设计参数灵敏度及取值研究

随着盾构隧道直径及幅宽的加大,综合考虑衬砌接头的传力及分布特性,传统的二维计算(梁-弹簧)模型已不足以更为全面地反映衬砌结构的空间力学特征。以ANSYS为平台,基于内置APDL和UIDL语言编制的"盾构管片衬砌三维分析程序"(3D Segment Lining Analysis Program of Shield Tunnel-SLAP 3D),建立壳-弹簧模型,对比分析地层参数(包括侧压力系数、地基抗力系数)、接头刚度参数(包括接头抗弯刚度、轴向抗拉压刚度、切向剪切刚度)对衬砌内力的影响,给出相关参数的取值原则。研究表明:进行衬砌内力计算时,接头抗弯刚度的取值宜通过工程类比或试验确定,在无法准确确定时可偏安全的取较大值;接头抗压、抗剪刚度在结构计算中可偏于安全的取大值。

Study on the Sensibility and Value of Design Parameters of Segment Lining of Shield Tunnel with a Large Section Based on the Shell-spring Model

Considering the increment of the diameter and breadth of shield tunnel and the load transferring and distribution character of lining joints,conventional two-dimensional(girder-spring)model cannot comprehensively reflect the space mechanical characteristics of lining structure.By using ANSYS software and based on 3D Segment Lining Analysis Program of Shield Tunnel-SLAP 3D internally installed APDL and UIDL languages,the study establishes a shell-spring model,contrastively analyzes the influence of formation parameters(covering lateral pressure coefficient and foundation resistance coefficient)and joint rigidity parameters(including joint flexural rigidity,tensile and pressure resistance rigidity in axial direction and tangential shear rigidity)on internal force of lining and puts forward the valuing principle of relevant parameters.The result shows that for internal force calculation,the value of joint flexural rigidity should be defined through engineering analogy or tests,and a larger value should be taken when lacks of accuracy;likewise,joint pressure resistance and shear rigidity can take a larger value for safety when making structural calculation.