既有铁路线与新建引水隧洞交叉及并行段施工力学特性研究  

Study on the Construction Mechanical Characteristic of a New Diversion Tunnel and Its Crossing and Parallel Section with an Existing Railway Tunnel

作　　者：张保卫[1] ZHANG Baowei(The Second Engineering Co.,Ltd.of China Railway 18th Bureau Group,Tangshan 064000,China)

机构地区：[1]中铁十八局集团第二工程有限公司,河北唐山064000

出　　处：《国防交通工程与技术》2025年第2期49-54,82,共7页Traffic Engineering and Technology for National Defence

摘　　要：针对西部地区某新建引水隧洞与既有铁路线隧道交叉、并行段的施工过程,采用FLAC3D有限差分程序,模拟并研究了隧道在不同横距、竖向间距条件下的内力和变形特征,重点分析了引水隧洞对隧道长距离并行段及下穿一号横洞段的施工影响。结果表明:在80 m竖向间距条件下,随着水平横距的增大(0~80 m),既有隧道衬砌结构的轴力与弯矩变化趋于稳定,结构内力影响减小;当横距超过40 m时,隧道衬砌的安全系数保持在规范要求范围内。引水隧洞下穿一号横洞时,强风化白云岩地层的低强度特性导致了围岩显著的竖向沉降,采用管棚加固措施后,隧道衬砌的竖向沉降和轴力显著降低,安全系数大幅提升。在复杂地质条件下,通过合理的施工设计和加固措施,可以有效控制类似交叉并行隧洞群施工引起的结构变形和内力变化,确保既有隧道结构的安全。This study investigates the construction mechanical characteristic of a newly built water diversion tunnel and an existing railway tunnel in a crossing and parallel section in the western region.Using the FLAC3D finite difference method,the internal force and deformation characteristic of the tunnel under different horizontal and vertical spacing conditions were simulated and analyzed.Special attention was given to the impact of tunnel construction in the long parallel section of the diversion tunnel and the section where it passes underneath Tunnel No.1.The results indicate that under a vertical spacing of 80 meters,as the horizontal spacing increases from 0 to 80 meters,the axial force and bending moment of the lining structure in the existing tunnel tend to stabilize,reducing the internal force impact.When the horizontal spacing exceeds 40 meters,the safety factor of the tunnel lining remains within the acceptable normative range.Additionally,when the diversion tunnel passes underneath Tunnel No.1,the low-strength characteristic of the heavily weathered dolomite formation lead to significant vertical settlement of the surrounding rock.After the application of canopy tube reinforcement,the vertical settlement and axial force of the tunnel lining are significantly reduced,and the safety factor is greatly improved.The findings demonstrate that under complex geological conditions,implementing rational construction design and reinforcement measure can effectively control structural deformation and internal force variations in cross-parallel tunnel groups,ensuring the safety of existing tunnel structure.

关 键 词：引水隧洞 下穿隧道 长距离并行 施工力学特性 

分 类 号：U455.4[建筑科学—桥梁与隧道工程]