内部结构施作方式对盾构隧道纵向力学特性的影响研究

Study on the Influence of Construction Methods of Internal Structures on Longitudinal Mechanical Characteristics of Shield Tunnels

为研究装配+现浇式内部结构和全现浇式内部结构的盾构隧道在超载下的纵向力学性能,以济南济泺路穿黄隧道及武汉三阳路隧道为工程背景,采用ABAQUS有限元软件建立围岩-管片-内部结构三维数值模型,并通过相似模型试验验证数值模型的合理性,对比分析不同内部结构施作方式下管片和内部结构的变形及力学特征,针对内部结构的损伤分布情况提出相应构件间连接的优化思路。研究结果表明:装配+现浇式内部结构分担的内力小于全现浇式结构分担的内力,管片承担的弯矩和剪力更大,导致管片的张开量和错台量均大于全现浇式,其中张开量的差异较为明显,较全现浇式的高10.02%~21.64%。此外,装配+现浇式内部结构由于应力集中影响更易出现局部损伤。当内部结构出现大面积损伤时,其加载区域承担的正弯矩下降,两端未破坏区域承担的负弯矩增大,结构的抗弯刚度降低,导致管片的弯矩值和环间张开量增大。

To study the longitudinal mechanical properties of shield tunnels with prefabricated assembly+cast-inplace internal structures and fully cast-in-place internal structures under overloading conditions,the Jinan Jiluo Road Yellow River Crossing Tunnel and Wuhan Sanyang Road Tunnel were taken as engineering backgrounds.A three-dimensional numerical model of the surrounding rock-segment-internal structure was established using ABAQUS finite element software,and the rationalityof the numerical model was verified through similar model tests.Comparative analysis of the deformation and mechanical characteristics of the segments and internal structures un⁃der different construction methods was conducted.Based on the damage distribution of the internal structures,opti⁃mization ideas for connections between components were proposed.The results show that the internal forces borne by the prefabricated assembly+cast-in-place internal structure are smaller than those of the fully cast-in-place structure.The bending moment and shear force borne by the segments are greater,resulting in larger openings and dislocations compared to the fully cast-in-place structure,with the difference in openings being particularly signifi⁃cant,10.02%~21.64%higher than the fully cast-in-place structure.Furthermore,the prefabricated assembly+cast-in-place internal structure is more prone to local damage due to stress concentration.When the internal struc⁃ture experiences large-scale damage,the positive bending moment borne by the loading area decreases,while the negative bending moment borne by the undamaged area at both ends increases,reducing the bending stiffness of the structure and increasing the bending moments and inter-ring openings of the segments.