复合地层双线地铁隧道施工地表沉降规律研究

Study on Ground Settlement Law of Double-line Subway Tunnel Construction in Composite Stratum

为提高地下空间利用率与施工效率,双线盾构隧道已广泛应用于城市地铁建设中。本文依托广州地铁某区段双线盾构隧道施工的工程背景,建立地层隧道三维弹塑性有限元模型进行施工过程数值模拟,并通过实测地表沉降数据验证计算结果;进而采用数值模拟研究上部软土下部灰岩复合地层中,双线隧道开挖过程中地表沉降的变化规律,分析双线隧道施工时两者之间的相互影响机制,基于叠加原理推导了双线隧道相对间距系数,结果表明通过该相对间距系数可判别地表沉降曲线形状,预测性分析两条隧道施工相互扰动影响程度,为广州地区软土灰岩复合地层双线盾构隧道施工的沉降监测与沉降控制提供了参考依据。

In order to improve the utilization of underground space and construction efficiency,double-line shield tunnels have been widely used in urban subway construction.Based on the engineering background of a double-line shield tunnel construction in a section of Guangzhou Metro Line 8,a three-dimensional elastoplastic finite element model of the stratum-tunnel is established to simulate the construction process,and the calculation results are validated by measuring the surface settlement data.The variation law of surface subsidence during the excavation of double-line tunnels in the soft soil complex of the lower soft soil is studied.The interaction mechanism between the two lines during the construction of the double-line tunnel is analyzed.Based on the superposition principle,the relative spacing coefficient of the double-line tunnel is derived.The results show that the shape of the surface settlement curve can be judged by the relative spacing coefficient,and the degree of mutual disturbance of the two tunnel constructions can be predicted,which provides a reference for settlement monitoring and settlement control of the double-line shield tunnel construction in the soft soil limestone composite stratum in Guangzhou area.