双线盾构隧道二次注浆对既有隧道结构影响研究

Study on the Impact of Secondary Grouting in a Double-line Shield Tunnel on the Existing Tunnel Structure

基于合肥市轨道交通2号线东延线三护区间平行下穿既有地铁2号线工程,采用FLAC3D软件构建盾构隧道精细化模型,分析不同二次注浆压力下盾构隧道下穿时对既有隧道结构沉降的影响。研究结果表明:二次注浆对既有隧道结构沉降有着显著影响,且注浆压力越大,影响效果越明显,为保证既有隧道结构的安全,注浆压力不宜过大,二次注浆压力应控制在0.3~0.4 MPa;二次注浆浆液配合比为水泥∶水玻璃∶水=0.5∶0.5∶1.0;盾构隧道下穿过程中,既有隧道结构最大沉降值与模拟值基本一致,且二者均呈减小趋势。研究结果可为新建盾构隧道下穿既有隧道结构设计提供一定的工程参考。

Based on Sanshibu StationHucheng Road Station section of east extension of Hefei metro line 2 parallel through the existing metro line 2,a sophisticated shield tunnel model was established by FLAC3D software to ana-lyze the impact of the through on the existing tunnel structural settlement under different secondary grouting pres-sures.The findings show that secondary grouting has a significant impact on the settlement of existing tunnel struc-tures.The higher the grouting pressure is,the more significant impact.In order to ensure the existing structural safety,it is recommended to maintain the grouting pressure within 0.3~0.4 MPa for secondary grouting;The mixing ratio of the secondary grouting slurry is cement:water glass:water=0.5:0.5:1.0;During the through,the maximum settlement value is basically the same as the simulation value.And both exhibit a decreasing trend over time.These research provide engineering reference for new shield tunnels through the existing tunnel structures design.