盾构穿越深厚垃圾填埋砂石坑技术方案研究

Study on technical scheme of shield tunneling through deep waste landfill

团九二期输水隧洞施工一标盾构穿越深厚垃圾填埋砂石坑,该地层组成物质来源复杂,结构疏松,施工沉降变形难以控制,风险极大。为了使盾构能够安全掘进穿越,进行补充勘察和人工挖孔勘察,确定了填埋物的组成成分、数量、强度和尺寸,进行了专项设计与施工。通过对明挖法、暗挖法和盾构法的比较,确定了采用盾构法施工;针对垃圾填埋地层松散的情况,采用地面注浆和洞内二次注浆等措施,使得松散的土体变得密实,保证了盾构机掘进过程中姿态稳定;通过对盾构机的适应性改造,加强刀盘的耐磨性和抗冲击性能,保证盾构在垃圾坑段正常掘进;同时,凭借监控量测等科学手段指导施工,及时调整盾构机掘进参数,成功解决了沉降难题,化解了工程风险。实际施工效果表明:通过土体改良和合理的盾构机改造,盾构机可以安全穿越深厚垃圾填埋地层。研究成果为盾构穿越垃圾坑地层等类似案例提供参考。

During the construction of water conveyance tunnel in Tuanjiu Phase 2,a standard shield tunnel crosses deep sand and gravel pits landfilled with garbage.This stratum has complex material sources,loose structure,difficult to control construction settlement and deformation,and great risk.In order to make shield tunneling safe,supplementary survey and manual excavation survey were carried out.The composition,quantity,strength and size of landfill were determined,and special design and construction were carried out.By comparing open-cut method,subsurface excavation method and shield tunneling method,shield tunneling method is adopted.In view of loose landfill stratum,ground grouting and secondary grouting are adopted to make loose soil compact and ensure the stability of attitude during shield tunneling.Through adaptability modification of shield tunneling machine,wear resistance and impact resistance of cutter head are strengthened.At the same time,relying on scientific means such as monitoring and measurement to guide construction,timely adjustment of shield tunneling parameters has successfully solved the settlement problem and solved the project risk.The actual construction results show that through soil improvement and reasonable shield machine transformation,deep landfill stratum can be safely traversed.The research results can provide reference for similar cases such as shield tunneling through the stratum of garbage pit.