Regarding the issues that existing studies on the longitudinal mechanical properties of shield tunnels rarely consider the longitudinal crossing of soft-hard mutation strata,and the influence law of the interface inclination angle remains unclear,a three-dimensional longitudinal refined model of the shield tunnel-strata is established based on the real project.Besides,a refined simulation method that simultaneously considers staggered segmental assembly,longitudinal and circumferential bolts,and the realistic mechanical property of the interface between the strata and the tunnel is proposed.The improved Timoshenko beam theory is used to verify the reliability of the model,the longitudinal mechanical properties of shield tunnels crossing soft-hard mutation strata are analyzed,and the influence law of the strata interface inclination angle is discussed.The results indicate that the settlement of shield tunnels changes abruptly at soft-hard strata interface and tends to be stable at both ends of the soft-hard strata.Moreover,the settlement difference between two sides of the tunnel is more significant when the inclination angle is 30° and 150°.The distribution of segment opening and dislocation is concentrated near the soft-hard strata interface,the range of which gradually shifts towards the soft soil layer as the inclination angle increases.The maximum segment opening and dislocation occur at an inclination angle of 120°,measuring 0.183 mm and 1.270 mm,respectively.The inclination angle has a significant impact on the longitudinal internal forces of the shield tunnel,becoming increasingly obvious when the angle exceeds 90°.The deformation of segment longitudinal bolts and the strata-tunnel interface is more noticeable in the longitudinal direction.The research results provide reference for further development of analysis methods for longitudinal shield tunnels and for ensuring the safe operation of similar shield tunnel projects.
关键词
盾构隧道/软硬地层/接触面倾角/纵向力学性能/精细化模型
Key words
Shield tunnel/Soft-hard strata/Interface inclination angle/Longitudinal mechanical properties/Refined model
维普
万方数据