南京纬三路过江通道盾构穿越长江堤岸地层变形及稳定性分析

Analysis of Stratum Deformation and Stability: A Case Study of the Nanjing Weisan Road River-Crossing Tunnel Passing under the Yangtze River Embankment

  • 摘要: 江河堤岸的地层变形及整体稳定性是过江盾构隧道施工时关注的重点。文章基于南京纬三路过江通道江北堤岸盾构段(S线)的工程背景,利用有限差分软件对施工过程进行了数值模拟,分析了盾构掘进对大堤地层沉降变形及整体稳定性的影响,并比较了不同注浆效果、堤岸坡度和隧道埋深情况下地层沉降变形及稳定性的差异。研究结果表明:地表沉降最大值在堤岸顶部中央位置,迎水面边坡产生沿隧道纵向位移,最大位移发生在堤岸边坡中点附近;盾构掘进使迎水面边坡安全系数降低,在盾构通过边坡前半段时,安全系数减小最显著;注浆效果、堤岸坡度和隧道埋深对堤岸沉降和边坡稳定影响具有差异性,注浆效果对地层沉降影响较大,隧道埋深次之,坡度影响很小;而坡度对于岸坡安全系数影响最大,注浆效果影响最小。

     

    Abstract: Stratum deformation and the overall stability of river embankments are key points in river-crossing shield tunnelling. Using the north river embankment section of the Nanjing Weisan Road river-crossing tunnel as an example, a numerical simulation of the construction process was made using finite difference software. This paper analyzes the influences of shield tunnelling on stratum deformation and overall stability of embankments, and compares settlement and stability differences under different grouting effects, slope coefficients and buried depths. The results show that: 1) the maximum settlement occurs at the center point of the top of the embankment and the maximum longitudinal displacement of the slope towards the water occurs near the midpoint of the slope; 2) the safety factor decreases with shield tunnelling at the slope towards the water, for which the trend is most significant at the front half of the slope; 3) the influence of the grouting effect on embankment settlement is significant, less so regarding the buried depth and minimal regarding the slope coefficient; and 4) the slope coefficient has the greatest influence on slope stability while it has the smallest influence on the grouting effect.

     

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