富水砂层盾构下穿股道桩筏加固控制效果研究

Study on the Pile Raft Reinforcement Control Effect of the Track Underpassed by the Shield in Water-Rich Sand Layer

以富水砂层地区南昌地铁盾构隧道下穿南昌火车站场为工程背景,利用Plaxis 3D建立基于小应变土体硬化刚度本构(HSS)的动态掘进模型,研究有无桩筏加固方案对盾构隧道下穿火车站场的影响。结果表明:盾构隧道在无保护措施下穿股道时,股道纵向沉降超过黄色预警值4.0 mm要求,最大值为5.2 mm,采取桩筏加固方案后纵向沉降最大值减小至1.4 mm,因此采用桩筏加固方案可有效确保股道行车安全。

A dynamic tunneling model based on small-strain harden soil stiffness(HSS)constitutive model was established by Plaxis 3D to study the influence of the pile raft reinforcement scheme on the Nanchang railway yard underpassed by the shield tunnel of the Nanchang Subway in the water-rich sand area.The results show that the longitudinal settlement of the track exceeds the yellow warning value requirement of 4 mm,with a maximum value of 5.2 mm,when the shield tunnel underpasses the track without any protection measures.The maximum value of longitudinal settlement is reduced to 1.4 mm after adopting the pile raft reinforcement scheme.Therefore,the pile raft reinforcement scheme could effectively ensure the traffic safety of the track.