上软下硬复合地层顶管施工技术研究

Research on Pipe Jacking Construction Technology in Upper Soft and Lower Hard Composite Stratum

如何在上软下硬不匀质岩层中确保顶进线路不发生偏移,管道不出现破损是顶管施工考虑的重要因素。结合具体工程,对城市上软下硬地层进行分析,针对分析出的原因,对上部软土地层地表加固、顶管机精准始发、管道减阻、裂缝处置、过程纠偏进行了研究。结果表明,采取地表注浆解决覆盖层厚度不足和机头偏移;通过增加千斤顶数量能解决上软下硬地层机头上移;通过加大顶管机刀头的开口率和提高泥浆比重,解决垃圾土堵塞问题;通过对管道加固,解决顶进过程中管道破损。这对同类工程的实际应用具有指导意义。

How to ensure that the jacking line does not deviate and the pipeline does not damage in the upper soft and lower hard uneven rock is an important factor for pipe jacking construction.In this paper,combined with specific projects,the city’s upper soft and lower hard strata are analyzed.According to the reasons analyzed,the surface reinforcement of the upper soft soil strata,pipe jacking machine accurate starting,pipeline resistance reduction,crack treatment,process correction are studied.The results show that surface grouting can solve the problem of insufficient overburden thickness and machine head offset;increasing the number of jacks can solve the problem of machine head moving up in the upper soft and lower hard strata;enlarging the opening rate of pipe jacking machine cutter head and increasing the mud proportion can solve the problem of garbage soil blockage;strengthening the pipeline can solve the pipeline damage in the jacking process.It has guiding significance for the practical application of similar projects.