不同施工顺序下小净距双线盾构隧道施工地层变形研究

    Study on ground deformation due to small-clearance twin shield tunneling with different construction sequences

    • 摘要: 不同施工顺序会导致周围地层应力重分布,引发地层变形问题。然而,现有研究主要聚焦单一的异步掘进或同步掘进双线隧道施工引起的地层变形,较少考虑不同施工顺序的影响。本文依托雄安新区某小净距双线盾构隧道工程,利用ABAQUS有限元软件建立数值模型,通过现场实测和Peck计算验证模型合理性,探究施工顺序对双线盾构隧道施工地层变形的影响。结果表明:施工顺序对地层竖向和水平位移均产生明显影响。地层竖向位移方面,与异步掘进相比,同步掘进的最大竖向位移(沿横截面)和沉降槽宽度系数分别增大34%~35%和20%~25%;竖向位移(沿纵截面)分别在地表和隧道下方0.5D处增大20%~33%和34%~58%。地层水平位移方面,与异步掘进相比,同步掘进在两隧道左、右两侧的最大水平位移增大46%~47%,在两隧道中间的最大水平位移几乎减小为0。

       

      Abstract: Different construction sequences can lead to stress redistribution in surrounding strata, triggering ground deformation problems. However, the existing studies mainly focus on the ground deformation caused by a single asynchronous or synchronous twin tunnel construction, and less consideration is given to the effects of different construction sequences. This paper relies on a small-clearance twin shield tunnel project in Xiong'an New Area, establishes a numerical model by using ABAQUS finite element software, verifies the reasonableness of the model through on-site measurements and Peck calculations, and investigates the effect of construction sequence on the deformation of the ground layer in the construction of twin shield tunnels. The results show that the construction sequence has significant influence on both vertical and horizontal displacements of the strata. In terms of vertical displacement, compared with asynchronous tunneling, the maximum vertical displacement (along the cross-section) and the width coefficient of the sinkhole of synchronous tunneling increased by 34%~35% and 20%~25%, respectively; the vertical displacement (along the longitudinal cross-section) increased by 20%~33% and 34%~58% at the ground surface and at the 0.5D below the tunnel, respectively. For the horizontal displacement of the ground, compared with asynchronous boring, the maximum horizontal displacement of synchronous boring on the left and right sides of the two tunnels increases to 46%~47%, and the maximum horizontal displacement in the middle of the two tunnels almost decreases to zero.

       

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