泥水盾构近接地下管线施工的管线沉降计算方法及管土位移规律研究

Research on calculation method of pipeline settlement and pipe-soil displacement law during slurry shield tunneling construction in proximity to underground pipelines

为更准确地预测管道受盾构开挖引起的竖向位移,对基于傅里叶变换的管道位移传递矩阵法进行修正,考虑泥水压力和注浆压力2个关键参数对管道位移的影响,并提出1种基于沉降监测数据的地层损失率的反演计算方法。同时,利用数值仿真软件FLAC3D分析不同工况下的管土变形规律,并与修正后的传递矩阵法进行对比。研究结果表明:由地层损失率反演计算方法可以计算得到较为准确和合理的地层损失率,使用该地层损失率计算地表沉降时与数值软件结果吻合度较高。修正后的传递矩阵法保留原计算方式的便捷性,同时考虑泥水压力和注浆压力等实际因素,与现场实测值更加贴近,准确度更高。管道与地层的相互作用可以通过管土相对刚度进行宏观定性描述,该参数可以反映出不同材质、壁厚、直径等条件下管道受盾构开挖影响的敏感性。研究结果可为盾构下穿既有管线的管线沉降预测提供一定参考。

To predict the vertical displacement of pipelines induced by shield tunneling more accurately,the modification is carried by using the transfer matrix method of pipeline displacement based on Fourier transform.Considering the influence of two key parameters of slurry pressure and grouting pressure on pipeline displacement,an inversion calculation method of ground loss rate based on settlement monitoring data is proposed.At the same time,the numerical simulation software FLAC3D is used to analyze the pipe-soil deformation law under different working conditions,and the results are compared with the modified transfer matrix method.The results show that the accurate and reasonable ground loss rate can be calculated by the inversion calculation method of ground loss rate,and the ground settlement calculated by the ground loss rate is in good agreement with the results of numerical software.The modified transfer matrix method retains the convenience of the original calculation method,and considers the actual factors such as slurry pressure and grouting pressure,which is closer to the field measured value and has higher accuracy.The interaction between the pipeline and the stratum can be qualitatively described by the pipe-soil relative stiffness,and this parameter can reflect the sensitivity of the pipeline to the influence of shield excavation under different materials,wall thicknesses,diameters and other conditions.The research results can provide some reference for the prediction of pipeline settlement of existing pipelines undercrossing by shield tunneling.