矩形顶管隧道邻近刚性管线施工安全距离研究

Research on Construction Safety Distance of Rectangular Pipe Jacking Tunnel Adjacent to Rigid Pipeline

针对顶管隧道邻近刚性管线施工安全距离问题,借助有限差分程序和梁—弹簧模型,采用两阶段法,对净空2.6 m×2.4 m矩形顶管电缆隧道在软黏土地层施工时土体变位特征进行研究,分析顶管平行下穿地下刚性管线时管—隧净距、管材和管径对刚性管线最大拉应力的影响,并根据服务年限对管线强度控制标准进行了修正,确定顶管下穿管线的安全施工距离。结果表明:管线最大变形曲率与最大拉应力随着顶管与管线间距的增大呈指数性衰减;同种材质下,管线管径越大,施工扰动导致的最大拉应力越大;管—隧净距及管线管径一定时,钢管的最大拉应力最大,球磨铸铁管其次,灰口铸铁管最小。

Aiming at the construction safety distance problem of pipe jacking tunnel adjacent to rigid pipeline,with the help of finite difference program and beam-spring model,using two-stage method,the soil change of a rectangular pipe jacking cable tunnel with a clearance of 2.6 m×2.4 m in soft clay ground is analyzed,bit characteristics were studied.The influence of the pipe-tunnel clear distance,pipe material and pipe diameter on the maximum tensile stress of the rigid pipeline was analyzed when the pipe jacking was parallel to the underground rigid pipeline.The safe construction distance of the pipeline under the pipe.It proued that:The maximum deformation curvature and the maximum tensile stress of the pipeline decay exponentially with the increase of the distance between the jacking pipe and the pipeline;Under the same material,the larger the diameter of the pipeline,the greater the maximum tensile stress caused by the construction disturbance.The greater the stress;when the clear distance between the pipe and the tunnel and the diameter of the pipeline are constant,the maximum tensile stress of the steel pipe is the largest,followed by the ductile iron pipe,and the gray cast iron pipe is the smallest.