The Influence of Excavation in Red Clay by Six Sections with CRD Method on the Vaults Subsidence and Structural Internal Force

Combined with the engineering practice of excavating a double-track railways tunnel in red clay, based on both numerical calculation by ANSYS software and monitoring data to study the variations of vaults subsidence, moment and supporting axial force in process of excavation. The results show that the ratio of vaults subsidence caused by excavation section 1 accounts for whole subsidence was about 36%, the vaults subsidence vs. time normally was a nonlinear uplifted curve with a final stable, the time of closing the tunnel invert play a decisive role in controlling vaults subsidence, closing the invert as soon as possible could greatly reduce the final subsidence. In the whole excavation process, the maximum moment appeared in the vault, the axial force caused by former excavation side (right side) was larger than that latter excavation side (left).