The construction of the Kunming Metro Line marks the first time China has built a tunnel in a soft layer containing peat soil using the shield method. Focusing on the engineering practices for this metro line, a corrected Peck formula is set up to calculate the ground surface settlement considering the influence of the construction of the first tunnel tube on the second tunnel tube in a soft layer containing peat soil. The law of ground settlement caused by shield construction is studied and compared to the empirical formula for ground settlement prediction. The results from this method and the numerical simulation agree very well with the measured data and can be used to analyze the shield-induced deformation law of soft ground containing peat soil. Compared to the change rate of ground surface settlement outside of the second tunnel tube, the change rate is larger for the first tunnel tube and its transverse settlement range is smaller, while the maximum settlement occurs between the center line of the two tunnel tube axes and first tunnel tube axis, and is caused by the construction of the first tunnel tube. Based on monitoring data from shield construction, the technical countermeasures against ground deformation caused by shield construction in soft stratum containing peat soil are proposed.%昆明地铁首次在含有泥炭质土软弱地层中采用盾构法施工,难度极大.文章依托昆明地铁首期工程实践,考虑含有泥炭质土软弱地层条件下先行隧道施工对后行隧道施工的影响,建立修正的Peck公式对地表沉降进行计算,在此基础上采用数值方法进一步分析该软弱地层条件下地铁盾构掘进引起地层沉降变形规律,并与地层沉降预测经验公式对比.研究表明:本文方法与数值模拟结果以及现场监测数据吻合较好,可以较好地分析含泥炭质土软弱地层中盾构掘进引起的地层变形规律;先施工隧道的外侧地表沉降变化率较大,后施工的隧道外侧地表沉降变化率较小,但横向沉降范围较大;最大沉降量位于两隧道轴线的中线和先施工隧道的轴线之间,主要由先施工的隧道引起.最后,结合盾构施工监测数据,提出了含泥炭质土软弱地层条件下地铁盾构施工地层变形控制技术措施.
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