机械顶管下穿河流时土体变形特征研究

Research on Soil Deformation Characteristics of Mechanical Pipe Jacking during River Crossing

以成都锦江再生水干管穿越河流顶管施工为研究背景,利用FLAC 3D软件模拟掘进,开展顶管施工数值分析。通过施工模型及其建模过程,研究顶管顶进时周边土体变形影响。结果表明,顶进过程中土体沉降沿掘进方向呈周期性变化,土体沉降量最大值发生在管道间接口处;不同泥水仓压力和注浆压力工况下,河道及两侧河岸地表沉降量以管道中线呈对称分布,管道上方地表沉降量最大,随着监测点向管道中线移动,地表沉降变化速率明显增大,且在中线附近变化速率显著减小。随着泥水仓压力的增大,土层变形量显著减小,而注浆压力的增大,土层变形量变化幅度较小。

The research background is the top pipe construction of the Jinjiang recycled water main pipe crossing the river in Chengdu,numerical analysis of pipe jacking construction was carried out using FLAC 3D software for excavation simulation.Through the construction model and its modeling process,the influence of surrounding soil deformation during pipe jacking was studied.The results show that the soil settlement during the jacking process varies periodically along the excavation direction,and the maximum soil settlement occurs at the interface between pipelines;Under different conditions of mud water tank pressure and grouting pressure,the surface settlement of the river channel and both sides of the river bank is symmetrically distributed along the centerline of the pipeline.The surface settlement above the pipeline is the largest.As the monitoring point moves towards the centerline of the pipeline,the rate of change in surface settlement significantly increases,and the rate of change significantly decreases near the centerline.As the pressure of the mud water tank increases,the deformation of the soil layer significantly decreases.As the grouting pressure increases,the change in the deformation of the soil layer is relatively small.