施工冷缝条件下富水铁路隧道结构裂损模拟分析

Simulation Analysis on Structural Cracking Damages of Railway Tunnels with Construction Joints in Water-rich Condition

为明确施工冷缝对富水运营隧道结构安全性的影响,文章以某典型铁路隧道病害为依托,运用FLAC3D软件建立仿真分析模型,研究有无冷缝、不同地下水头高度等因素对衬砌结构内力、安全系数及变形模式的影响规律。结果表明:该隧道病害不仅与地表集中降雨导致地下水位抬升有关,还与衬砌结构既有缺陷(施工冷缝)存在明显关系;施工冷缝的存在不仅会改变原有衬砌承载模式,导致有冷缝侧轴力明显增大,弯矩存在突变,还会引发衬砌结构变形模式的变化,致使衬砌结构易沿冷缝面发生错动滑移,出现局部衬砌向内弯折变形破坏。

To clarify the influence of construction joints on the structural safety of operating tunnels in water-rich condition,taking a typical railway tunnel defects as the basis this paper uses the FLAC3D software to establish a simulation analysis model,and studies the influence laws of the internal forces,safety coefficients and deformation patterns of the lining structures with/without construction joints and under different groundwater heights.The re⁃search results show that the occurrence of the tunnel defects is not only due to the rising of the groundwater level caused by concentrated rainfall on the ground surface,but is also significantly related to existing defects(construc⁃tion joints)in the lining structure;the existence of construction joints will not only change the original bearing mode of the lining,resulting in the significant increase of the axial force at the side of the construction joints and abrupt change of the bending moment,but also change the deformation mode of the lining structure,in which case the lin⁃ing structure would be prone to misalignment slip along the surface of construction joints,and part of the lining structure would be bent inward,causing deformation damage.