摘要
针对高埋深富水砂性土层盾构隧道施工中土体的加固困难,提出了一种采用冻结水泥土桩法对端头进行加固的方法,并以某引水隧洞工程为例,基于FLAC 3D模拟分析了冻结水泥土桩法加固后的盾构始发端头土体的位移变化。研究表明,-5、-10、-15、-20℃等4种冻结工况下,洞门凿除后掌子面土体纵向最大位移和塑性区面积均较小,土体稳定性较好,且变形明显减小的转折点在-5^-10℃之间。对比传统的常温水泥土桩加固,洞门凿除后掌子面土体纵向最大位移减小97%,说明采用冻结水泥土桩法相比传统方法加固效果大大提升。冻结水泥土桩加固后,盾构穿过加固区后的隧道拱顶向上的土体位移很小,表明冻结后加固区土体的强度增大,大大提高了盾构开挖后周围土体的稳定性。
Aiming at the problem of soil reinforcement in shield tunnel construction in high buried deep water rich sandy soil layer,a method of using frozen cement soil pile to reinforce the end was proposed.Taking a diversion tunnel project as an example,the displacement change of the soil at the beginning of shield tunnel reinforced by frozen cement soil pile method was simulated and analyzed based on FLAC 3D.The results indicate that the maximum longitudinal displacement and plastic zone area of the soil on the face of the palm are very small after the excavation of the tunnel portal under the four freezing conditions of-5、-10、-15 and-20℃,which prove the stability of the soil,and-10℃is the turning point for the obvious reduction of deformation among these four conditions.Compared with the traditional reinforcement with normal temperature cement soil pile,the maximum longitudinal displacement of the soil on the palm face is reduced by more than 97%,which indicates that the effect of freezing cement soil pile reinforcement is greatly improved compared with the traditional method.After strengthening with frozen cement soil piles,the displacement of the soil upward from the arch top of the tunnel after shield passing through the reinforcement area is very small,which indicates that the strength of the soil in the reinforcement area increases after freezing and greatly improves the stability of the surrounding soil after shield excavation.
作者
古小辉
李乐晨
李子阳
GU Xiaohui;LI Yuechen;LI Ziyang(Henan NO.2 Hydraulic Engineering Bureau,Zhengzhou 450016,China;Department of Engineering Mechanics,Columbia University,New York NY10027,USA;State Key Laboratory of Hydrology Water Resources and Hydraulic Engineering,Nanjing Hydraulic Research Institute,Nanjing 210098,China)
出处
《人民黄河》
CAS
北大核心
2019年第11期127-130,143,共5页
Yellow River
基金
国家重点研发计划项目(2016YFC0401602)
国家自然科学基金资助项目(51779155,51779151,51609150)
关键词
富水砂层
端头加固
冻结水泥土桩法
数值模拟
water rich sand layer
end reinforcement
freezing cement soil pile method
numerical simulation
