ANALYSIS OF EFFECTS OF SHIELD TUNNEL CONSTRUCTION PROCESS AND SUPPORTING WAYS ON PILE GROUPS OF HIGH-SPEED RAILWAY VIADUCT

According to one of the Beijing subway section which crossed the high-speed railway, the impact of choosing different shield parameters and tunneling support conditions on the force and deformation of pile group is analyzed. In the pre-engineering test section of the tunnel excavation, the relationship between the shield parameters and equivalent layer in finite element calculation is established. Six different construction conditions of different equivalent layers and the existence of isolated piles are analyzed. The effect of optimizing the shield parameters and using isolated pile on the pile group in shield tunnel excavation is described. The analysis result indicates that: 1) Optimizing the shield parameters and using isolated pile has a significant effect on controlling the bending moment, horizontal displacement, axial force and settlement. However, the isolated pile has better effect than shield parameter optimization; 2) The isolated pile basically eliminates the dynamic changes in the moment of the pile during tunneling. It also makes uniform the effect on the displacement of the pile group during tunneling; 3) The monitoring results show that the numerical results reflect the actual excavation process well. The final calculated settlement value is very close to the measured cumulative value.