盾构施工引起周围土体位移的数值研究

Numerical Study on Ground Displacement Induced by Shield Tunneling

盾构隧道施工会引起周围地层及地表变形并影响周围环境,为探索变形规律以进行预测,运用岩土数值软件FLAC3D建立三维模型,考虑天津地区软土特性,注浆体材料强度的时空变化特性及盾构施工中的各相关作用进行研究。首先建立标准模型进行分析,并与Loganathan公式计算及工程实测数据计算进行对比验证,然后就重要施工参数如超挖孔隙、注浆压力等的影响,不同土体本构关系对计算结果的影响,土体修正剑桥模型参数如超固结比、内摩擦角、压缩参数λ及回弹参数κ的影响进行了研究,将结果与已有的研究结果进行比较,具有较好的一致性。

Shield-driven tunneling will result in stratum deformation and ground surface settlements,affecting adjacent buildings and pipelines.To investigate the deformation mechanism for prediction purposes,a 3D model was established using the finite difference software FLAC3D,and the characteristics of Tianjin soft soil,the spatiotemporal variation of the strength of grouting material,and the related influencing factors in shield construction are considered.First,a“standard problem”was established and analyzed;the results were compared and validated with the Loganathan formula and measured data.Then,the influence of various factors were studied,including important construction parameters such as pores induced by over excavation,grouting pressure,different soil constitutive models,and parameters of the modified Cam-clay model such as the over consolidation ratio and internal friction angle.In summary,this paper elucidated the effect of several vital parameters on the ground surface settlements and horizontal ground displacements.The results fit well with previous research findings and make new progress.