大直径顶管施工管土相互作用实测分析——以佛山市电力隧道顶管工程为例

Measurement Analysis of Pipe-Soil Interaction in Large-Diameter Pipe Jacking Project of a Power Tunnel in Foshan,China

为研究大直径顶管在深埋高水压工况下的管节荷载变化,结合佛山市电力隧道顶管工程,对顶管施工过程中管节荷载、孔隙水压力进行实测分析,并比较现行各规范理论计算结果和实测管节荷载的区别,推导在注浆状态下管节荷载的计算方法。监测数据及计算结果表明:1)管节荷载在管壁四周分布较均匀,管节顶部荷载的变化受注浆压力影响较小,管节底部荷载与注浆压力变化基本一致,且管节底部荷载变化大于注浆压力的变化;2)管土接触状态在注浆顶进过程中符合隧洞稳定假设,顶进结束停止注浆后更符合管土全接触假设;3)在注浆状态下,各规范计算的管节荷载相比实测值较小,采用太沙基被动土拱理论推导的管节荷载计算模型更加合理。

To study the change in the segment load of large-diameter pipe jacking under deep-buried and high water pressure conditions,a case study is conducted on the pipe-jacking project of a power tunnel in Foshan,China.Further,the segment load and pore water pressure of the segment during pipe-jacking construction are measured and analyzed,and the results are compared with the theoretical calculation results in the current specifications.Then,the calculation method of segment load under grouting condition is deduced.The monitoring data and calculation results show the following.(1)The joint load of the segment is evenly distributed around the pipe wall,the top load is less affected by the grouting pressure,the bottom load accords with the grouting pressure,and the change of the bottom load is greater than that of the grouting pressure.(2)The state of pipe-soil contact accords with the tunnel stability assumption during grouting jacking,and it fully accords with the pipe-soil interaction assumption when grouting stops at the end of jacking.(3)Under the grouting condition,the segment load calculated by each specification is smaller than the measured values,and the pipe load calculation model by Terzaghi passive soil arch model is more reasonable.