: 为研究盾构隧道纵向计算模型中螺栓-凹凸榫型式环缝接头刚度的非线性力学特性,分别建立管片环缝张开与错台模式下 的环缝接头计算模型,通过分析不同环缝变形状态下接头连接构件力学特征,得到环缝抗拉和抗剪刚度的非线性规律;环缝接头采 用非线性抗拉、抗剪弹簧模拟,构建基于三维实体-非线性弹簧单元的盾构隧道纵向沉降计算模型,并将其用于评价地面堆载对厦 门地铁2号线滨海区段管片结构安全的影响。 结果表明,对于外径6.7 m、内径6 m、环宽1.5 m、环缝由M30螺栓连接的盾构隧道: 1)环缝张开超过1.78 mm时,接头抗拉刚度降低为设计值的1%; 张开超过10.2 mm时,可认为抗拉失效。 2)环缝错台小于6 mm 时,抗剪刚度基本不变; 错台超过9.7 mm后,抗剪刚度降低至约为设计值的25%; 错台超过30 mm时,可认为抗剪失效。 3)隧道 轴线方向的地表超载范围为 d,管片纵向变形受影响范围为±3d,轴线50环管片差异沉降小于23 mm时,可满足曲率半径不小于 《城市轨道交通结构安全保护技术规范》控制值15 000 m。

In order to study the nonlinear mechanical properties of the joint stiffness with bolt-concave and convex tenon type in the longitudinal calculation model of shield tunnel, the calculation models of the annular joints under the opening mode and the dislocation mode are established respectively. By analyzing the mechanical characteristics of the joints under different deformation conditions, the nonlinear laws of tensile and shear stiffness of the joints are obtained. The calculation model of shield tunnel longitudinal settlement based on three-dimensional entity-nonlinear spring element is constructed by using nonlinear tensile and shear spring simulation of annular joint; and the model is used to evaluate the influence of surface overload on the safety of segment structure in coastal area of Xiamen Metro Line No. 2. The results show that for the shield tunnel of which the outer diameter is 6.7 m, the inner diameter is 6 m, the ring width is 1.5 m, and the annular joint is connected with M30 bolts: (1) When the opening of the annular joint exceeds 1.78 mm, the tensile stiffness of the joint decreases to 1% of the designed value; and when the opening of the joint exceeds 10.2 mm, the tensile failure can be considered. (2) The shear stiffness is almost unchanged when the amount of dislocation is less than 6 mm, and the shear stiffness decreases to about 25% of the designed value when the amount of dislocation is over 9.7 mm; when the amount of dislocation is over 30 mm, the shear failure can be considered. (3) When the overloading range of the tunnel axis is d, the longitudinal deformation of the segment is affected by ±3d, and the differential settlement of the 50-ring segment of the tunnel axis is less than 23 mm, the curvature radius is not less than 15 000 m.