盾构隧道下穿对高速铁路CFG桩复合路基影响规律研究OA北大核心CSTPCD

Addressing the unclear response mechanism of CFG pile composite roadbed to groundsettlement and the lack of theoretical foundation for predicting and controlling roadbed settlement during the construction of urban subway tunnels beneath high-speed railways, this study leverages the engineering project where the Zhengzhou Rail Transit Line 8 shield section crosses under the throat area of Zhengzhou East Railway Station. It introduces a method for predicting the settlement of CFG pile composite foundations. Analyzing the reinforcement effect of CFG piles on the roadbedbased on ground reinforcement theory and employing physical model experiments, this research in-vestigates the pattern of influence exerted by shield tunnel crossings on the CFG pile composite foun-dations of high-speed railways. The research results indicate that CFG piles significantly enhance the roadbed's compression modulus without compromising the composite foundation's integrity. The deformation pattern of the composite roadbed aligns with Peck's settlement curve. Addition-ally, CFG pile composite roadbed increase the ground layer's equivalent internal friction angle by approximately 50％, thus reducing ground settlement by about 23％. The maximum settlement in-duced by shield tunnel crossings in the CFG pile composite foundation is recorded at 1.65 mm. Sig-nificant ground settlement deformation begins when the shield tunnel face is 10 m from the roadbed centerline, with 83.6％ of the settlement occurring during the shield crossing phase. As the shield moves away, the settlement of the roadbed continues to increase, suggesting the need for settlement monitoring to persist until stabilization is achieved. These results offer valuable insights for the settlement prediction and reinforcement of CFG pile composite roadbed in scenarios involving shield tunnel underpassing high-speed railways.