基于薄壁圆柱壳理论的盾构隧道抗震拟静力分析法
Pseudo-static analysis method for shield tunnels based on theory of thin-walled cylindrical shell
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摘要: 为简化盾构隧道抗震分析,在获得深埋盾构隧道周边自由场剪应变和剪应力的基础上,基于弹性薄壁圆柱壳理论,给出了求解深埋盾构隧道水平地震剪切波作用下的附加内力计算公式,并与同等条件等效刚度数值分析方法结果进行了对比。研究表明:滑移和不滑移条件下的拟静力计算结果与相应的数值分析结果具有良好的一致性,说明基于弹性薄壁圆柱壳理论获得的盾构隧道拟静力公式具有良好的合理性。研究还表明:水平地震剪切波作用下,可滑移条件下的附加弯矩和附加剪力分别大于不滑移条件下的附加弯矩和附加剪力,可滑移条件下的附加轴力小于不滑移条件下的附加轴力;附加弯矩和附加轴力呈现反对称分布特性,其最大值通常分布在45°和225°雷达对称轴或135°和315°雷达对称轴上,附加剪力最大值一般分布在0°和180°雷达对称轴上。研究结论对盾构隧道工程抗震设计具有一定的参考价值。Abstract: To simplify the aseismic analysis of deeply-buried shield tunnels, a formula is proposed for solving the additional internal force in the tunnel linings of a deeply-buried shield tunnel under horizontal seismic shear waves based on the acquisition of the shear strain and shear stress of free-field around it and the utilization of the theory of elastic thin-walled cylindrical shell. Then, a model of numerical analysis of equivalent stiffness under the same condition is established for comparison. The research shows that the pseudo-static and numerical results have a good consistency under full slip and no slip conditions. The proposed pseudo-static formula for shield tunnels based on the theory of elastic thin-walled cylindrical shell is reasonable. Meanwhile, under the horizontal seismic shear waves, the additional bending moment and shear under full slip are larger than those under no slip, and the additional axial force under no slip is larger than that under full slip. The additional bending moment and axial force exhibit features of antisymmetric distribution, and their maximum values distribute on radar axis of 45°and 225°or 135°and 315°, and the maximum values of shear distribute on radar axis of 0°and 180°. The research results have certain reference value for the seismic design of shield tunnel engineering.