摘要
在富水地区修建隧道工程时,高水压力对衬砌结构安全有极大的影响。目前,隧道断面设计仍停留在对隧道的单一指标进行设计比选的阶段,然而事实上隧道断面的最优选择必须考虑包括围岩形态响应应力、位移、稳定性等多方面因素的影响。首先利用有限元差分软件建立南大梁高速工程某隧道断面在不同扁平率下的数值模型,研究8种扁平率下隧道衬砌内力和围岩位移、塑性区等情况;其次采用层次分析法对隧道关键部位的围岩位移、衬砌弯矩、衬砌轴力、孔隙水压力和围岩塑性区的目标值加以调整,从而获得隧道在地层条件为高压富水硬岩时的扁平率最优值。研究表明,当隧道处于高压富水硬岩地层中时,不同扁平率下隧道衬砌弯矩分布基本一致,弯矩反弯点均出现在拱腰、拱脚附近,隧道扁平率的改变对拱腰处弯矩值影响最大,最大变化幅值可达到70.8 kN·m;仰拱隆起值随着扁平率的增大逐渐减小,隧道两侧水平收敛、最大轴力值、最大孔隙水压力值以及塑性区面积均随着扁平率的增大先增大后减小,拱顶下沉值受扁平率变化的影响较小;从施工成本、隧道抗压承载能力、结构安全性3个角度出发,综合考虑隧道尺寸、洞周衬砌应力分布、洞周变形位移、初期支护安全性和衬砌结构安全性等因素,结合组合权重分析,依托工程隧道断面的最优扁平率为0.82。本研究技术和结论将为高压富水硬岩地层中隧道结构断面施工的参数优化方案提供参考。
High water pressure has a great impact on the safety of the lining structure when the tunnel is built in the rich water area.At present,the tunnel section design is still in the stage of comparing the design of a single index of the tunnel,but in fact,the optimal selection of the tunnel section must consider the influence of many factors,including the response stress,displacement and stability of the surrounding rock form.Firstly,the numerical model of a tunnel section in Nandaliang high-speed project under different flattening rates is established by using finite element difference software,and the internal force of tunnel lining,displacement of surrounding rock and plastic zone are studied under 8 flattening rates.Secondly,analytic hierarchy process is used to adjust the displacement of surrounding rock,lining bending moment,lining axial force,pore water pressure and target value of plastic zone of surrounding rock in the key parts of the tunnel,so as to obtain the optimal flattening rate of the tunnel in the case of high-pressure water-rich hard rock formation.The results show that when the tunnel is in the high-pressure water-rich hard rock formation,the bending moment distribution of the tunnel lining is basically the same under different flattening rates,and the reverse bending points of the bending moment all appear near the arch waist and arch foot.The change of the flattening rate has the greatest influence on the bending moment value at the arch waist,and the maximum variation amplitude can reach 70.8 kN·m.Horizontal convergence,maximum axial force,maximum pore water pressure and plastic zone area on both sides of the tunnel first increase and then decrease with the increase of the flattening rate.The arch subsidence value is less affected by the change of the flattening rate.From the three perspectives of construction cost,tunnel compressive bearing capacity and structural safety,the optimal flattening rate of the tunnel section based on the combined weight analysis is 0.82,considering the tunnel size,stress distribution around the tunnel lining,deformation displacement around the tunnel,initial support safety and lining structure safety and other factors.This research technique and conclusion will provide reference for the parameter optimization scheme of tunnel structure section construction in high-pressure water-rich hard rock stratum.
作者
朱鹏霖
孙意
申玉生
张昕阳
谢俊
曹珂
ZHU Penglin;SUN Yi;SHEN Yusheng;ZHANG Qinyang;XIE Jun;CAO Ke(Key Laboratory of Transportation Tunnel Engineering of the Ministry of Education,Southwest Jiaotong University,Chengdu 610031,China;China Communications Railway Design and Research Institute Co.,Ltd.,Beijing 100088,China;China Railway Siyuan Survey and Design Group Co.,Ltd.,Wuhan 430063,China)
出处
《铁道标准设计》
北大核心
2025年第2期128-135,共8页
Railway Standard Design
基金
国家重点研发计划项目(2019YFC0605104)
中铁第四勘察设计院集团有限公司科研课题(2022K005,2022K006)
中国铁建股份有限公司科研计划课题(2020-B17)。
关键词
隧道工程
富水地层
有限元
层次分析法
扁平率
参数优化
tunnel engineering
water-rich strata
finite element
analytic hierarchy process
flat rate
parameter optimization
