盾构管片开口解析分析方法及其应用

Analytical Solution of Tunnel Linings Subjected to Opening Condition and Its Application

为方便隧道中人员和车辆在灾害中能就近逃生和避险,需要设置大量的地下结构联络通道,这就带来了盾构隧道管片开口问题。采用Timoshenko曲梁理论描述管片的力学行为,通过土弹簧和荷载模拟周围土体对隧道的约束和加载作用,三向弹簧模拟环内纵缝接头,均布剪切弹簧模拟环间接头,建立了分析模型。首先采用状态空间法,推导了不考虑开口时多环衬砌传递方程。其次引入自由边界条件,调整荷载和系统矩阵,导出了考虑开口工况和错缝拼装的多环衬砌传递方程,得到了开口工况下盾构隧道的响应。最后结合之江路联络通道工程,通过数值算例,验证所提方法的同时分析了大直径盾构隧道开口工况下开口环和邻近环的变形和内力分布规律,研究了地质条件和环间连接情况对衬砌开口的影响。结果表明:开口环位移增加而内力减小,邻近环则位移和内力都增加;周围地质条件越好,隧道受开口工况的影响越小。在实际工程中,可以通过增强环间连接的方法来减小开口工况对于衬砌受力的影响。

To facilitate the evacuation and shelter of vehicles and personnel in the tunnel during calamity,it was necessary to construct cross passages,leading to difficulties associated with the tunnel opening.In the analytical model,the Timoshenko curved beam theory was used to describe the mechanical behavior of the tunnel segment,soil springs and loads were used to model the constraint and loading effect of the surrounding soil acting on the tunnels,a set of three-directional springs were used to model the longitudinal joints between the segments,and shear springs with both radial and circumferential resistances were used to model the circumferential joints between the adjacent rings.Based on the state space method,the transfer function,without considering the opening effect,was derived first.Then by introducing the free boundary condition and adjusting the load and system matrices,the transfer function considering the opening and staggered assembly effects was derived,and the mechanical behavior of tunnel lining was determined.Combined with the Zhijiang Road cross passages project,numerical examples were presented to verify the reliability of the proposed method.Then the opening condition of large diameter shield tunnel was analyzed,and the deformation and internal force distribution of the opening ring and adjacent rings were presented.Finally,the influence of geological conditions and connections between rings were studied.The analytical results indicate that the opening of shield tunnel can increase the displacement but decrease the internal force of the opening rings,while both the displacement and internal forces of the adjacent rings are increased.Moreover,the tunnel lining is less affected by the opening condition for a more optimized surrounding geological condition.The detrimental effects of the opening condition on tunnel lining can be considerably reduced by reinforcing the connections between rings in practical engineering.