超浅埋富水砂层地铁隧道开挖安全控制技术研究

Research on Safety Control Technology of Subway Transverse Channel Excavation in Ultra-shallow Buried Water-rich Sand Layer

文中针对超浅埋富水砂层浅埋暗挖易失稳的施工难题,提出“洞内洞外水平钻孔前进式分段注浆+超前管棚+CRD工法”的安全控制方法,该方法钻孔及注浆施工均在洞外完成,与洞内开挖不交叉作业,极大提高了施工效率。采用数值模拟进一步分析了不同注浆加固厚度以及开挖步距下围岩的位移场、应力场变化规律,提出了合理的施工参数,并成功运用于某城市地铁横通道开挖。现场监测数据表明该方法地层变形控制效果良好,且可以提高施工效率。

This paper proposes a full-section pre-grouting reinforcement method of "advance pipe shed + horizontal drilling in and out of the tunnel advanced sub-grouting",which is suitable for the construction of urban subway sand underground transverse passages.The slurry construction is completed outside the cave,and does not intersect with the excavation construction in the cave,which greatly improves the construction efficiency.Numerical simulation is used to analyze the displacement field and stress field change law of surrounding rock under different grouting reinforcement thickness and excavation step by CRD method,and reasonable construction parameters are proposed and successfully applied to the sand excavation of a transverse channel.The results show that the surface deformation control effect of this scheme is good,and the construction efficiency can be improved.