软弱地层下穿盾构施工隧道对既有铁路路基变形的影响分析

Analysis of the impact of shield construction tunnels under softstrata on the deformation of existing railroad roadbeds

基于长春地铁2号线某盾构区间下穿长双烟铁路工程研究软弱地层下盾构隧道下穿施工引起上部铁路路基沉降的影响规律,采用FLAC3D有限元软件进行模拟,研究铁路路基在不同施工工况下的沉降分布规律,并分析了土仓压力、注浆压力及深孔注浆加固作用下铁路路基的沉降影响。分析结果表明:盾构左线施工对铁路路基的扰动大于盾构右线施工;既有铁路路基的沉降量不受土仓压力的影响,但随着注浆压力的增加而降低;采用深孔注浆加固后铁路路基的最大沉降量满足《普速铁路线路修理规则》中的规定。分析结果可为软弱地层条件下盾构下穿铁路路基施工提供一定的参考依据。

In order to study the influence of the settlement of the upper railroad foundation caused by the shield tunnel construction under the soft ground,based on the Changchun Metro Line 2,a shield tunnel interval under the Changshuangyan Railway project,FLAC3D finite element software is used to simulate and study the settlement distribution of the railroad foundation under different construction conditions,and analyze the influence of the settlement of the railroad foundation under the effect of soil bin pressure,grouting pressure and deep hole grouting reinforcement.The analysis results show that:the disturbance of the left line of shield construction on the railroad roadbed is larger than the right line of shield construction;the settlement of the existing railroad roadbed is not affected by the soil bin pressure,but decreases with the increase of grouting pressure;the maximum settlement of the railroad roadbed after the reinforcement with deep hole grouting meets the provisions of the“Rules for Repairing the Lines of General-Speed Railways”.The analysis results can provide certain reference basis for the construction of shield structure under the railroad roadbed under the condition of soft stratum.