摘要
随着交通运输需求的提高,现有线路的运能难以满足运营要求,需开展增建二线工程进行扩能改造。作为隧道力学行为的主要影响因素,确定合理净距尤为重要。因此,对铁路增建二线工程隧道合理线间距展开研究,为增二线隧道净距设计提供依据和量化标准。考虑到目前在铁路增二线工程方面缺乏针对性研究,首先对相似工程进行调研作为参考,并建立既有隧道变形、劣化情况等控制标准进一步指导合理线间距取值。基于偏压荷载模型对新建明挖隧道展开分析,建立以新建明挖隧道基坑边坡为联系的隧道净距与既有隧道外侧拱肩山体覆盖厚度的对应关系。之后建立二维平面模型进行数值分析,探究不同间跨比工况下地表变形、既有隧道拱脚差异沉降的变化规律和塑性区发展情况。模拟结果表明,Ⅴ级围岩软岩条件下,随间跨比增大,地表沉降和既有隧道拱脚差异沉降曲线均显著减小,且间跨比>2.5时,曲线趋于稳定;两隧道塑性区先贯通后分离,间跨比等于1.5时首次分离,后逐渐减小,间跨比>2.5时两塑性区形态基本稳定。将沉降曲线斜率和塑性区形态保持稳定处作为评定标准,同时结合实际工程需求和地质情况,最终提出Ⅴ级围岩软岩对应隧道净距合理取值范围为(2.0~3.0)B(B为隧道开挖断面宽度)。综合分析下,最终提出一般暗挖和明挖段增建二线工程的隧道净距建议值。
With the increasing demand for transportation,the capacity of existing lines can no longer meet operational requirements,necessitating the implementation of the added second line project for capacity expansion.As a primary influencing factor of the mechanical behaviors of tunnels,determining the reasonable clear distance is particularly important.Therefore,this study investigated the reasonable line spacing of tunnels for railway added second line project,providing a basis and quantitative standards for the clear distance of added second line tunnels.Considering the current lack of targeted research on the railway added second line project,similar projects were first investigated as references,and control standards for deformation and deterioration of existing tunnels were established to further guide the determination of the reasonable line spacing.Based on the eccentric loading model,the new open-cut tunnel was analyzed.A correlation between the tunnel clear distance and the overburden thickness at the outer arch shoulder of the existing tunnel was established,linked by the slope of the foundation pit of the new open-cut tunnel.Subsequently,a two-dimensional plane model was established for numerical analysis to investigate the variation patterns of ground deformation,differential settlement at the arch foot of the existing tunnel,and the development of plastic zones,under different spacing-to-span ratio conditions.The simulation results showed that under Grade V surrounding rock,with increasing spacing-to-span ratio,both the ground settlement curve and differential settlement curve at the arch foot of the existing tunnel decreased significantly,and the curves tended to stabilize when the spacing-to-span ratio exceeded 2.5.The plastic zones of the two tunnels were first connected and then separated,with initial separation occurring at a spacing-to-span ratio of 1.5,followed by gradual reduction.When the ratio exceeded 2.5,their morphology remained basically stable.The slope of the settlement curve and the stabilized morphology of plastic zones were taken as evaluation criteria.Combined with actual engineering requirements and geological conditions,the reasonable clear distance range of tunnels in Grade V surrounding rock was determined to be(2.0~3.0)B(B is the width of tunnel excavation face).Based on the comprehensive analysis,the recommended values for the tunnel clear distance in both typical underpass and open-cut sections of the added second line project were finally proposed.
作者
杨克文
于晨昀
杨昕睿
李鹏飞
YANG Kewen;YU Chenyun;YANG Xinrui;LI Pengfei(China Railway Engineering Design and Consulting Group Co.,Ltd.,Beijing 100055,China;Key Laboratory of Urban Security and Disaster Engineering,Ministry of Education,Beijing University of Technology,Beijing 100124,China)
出处
《铁道标准设计》
北大核心
2025年第10期103-110,149,共9页
Railway Standard Design
基金
中铁工程设计咨询集团有限公司2022年度科技开发计划(2022-24)。
关键词
铁路隧道
增建二线
合理线间距
数值模拟
明挖隧道
加固措施
railway tunnel
added second line
reasonable line spacing
numerical simulation
open-cut tunnel
reinforcement measures
作者简介
杨克文(1988-),男,高级工程师,2013年毕业于北京交通大学桥梁与隧道工程专业,工学硕士,主要从事铁路、市政等隧道及地下工程设计、科研和技术管理工作,E-mail:yangkewen@me.com。
