隧道支护加固参数对上部输气管线影响分析

Analysis on the Influence of Tunnel Support Reinforcement Parameters on the Upper Gas Pipeline

基于有限元软件MIDAS GTS NX和正交试验设计方法,建立新奥法隧道施工下穿输气管线模型,分析时以管线的变形和应力为指标,利用极差和方差分析探讨管隧正交情况下不同支护加固参数(加固范围、加固厚度、喷混厚度、喷混强度等级、二衬强度等级、初支距掌子面距离)对上部管线变形的影响。结果表明:隧道加固范围和初期支护距掌子面距离对管线变形和应力的影响极为显著,加固范围从90°增加至360°,管线位移和最小主应力的减小幅度均超过69%;初期支护距掌子面的距离从1 m增加至4 m,管线竖向位移和最小主应力急剧增大,增幅均超过1倍;加固厚度、喷射混凝土强度等级对管线变形和应力的影响高度显著,喷射混凝土厚度影响显著,二次衬砌强度等级影响不显著。

Based on the finite element software MIDAS GTS NX and the orthogonal test design method,a NATM model of tunnel construction under pass gas pipeline is established.The influence of different supporting and strengthening parameters(strengthening range,reinforcement thickness,shotcrete thickness,shotcrete strength grade,secondary lining strength grade,initial support distance from the working face)on the deformation of the upper pipeline is discussed by using range and variance analysis.The results show that:the influence of the strengthening range and the distance of the initial support from the working face on the deformation and stress of the pipeline is very significant,the reinforcement range increases from 90°to 360°,the reduction of the pipeline displacement and the minimum principal stress are more than 69%;the distance of the initial support from the working face increases from 1 m to 4 m,the vertical displacement and the minimum principal stress of the pipeline increase sharply,the increase is more than double.The effects of reinforcement thickness and shotcrete strength grade on pipeline deformation and stress are highly significant,while the effects of shotcrete thickness are significant and the effects of secondary lining strength grade are not significant.