Grinding pile technology of shield tunnels crosssing pile foundation of existing bridges

Based on the construction requirements of the shield tunnel crossing 6 large-diameter bridge piles of Fengqi bridge in the section of Jianguo Road Station-Zhonghe Road Station of Hangzhou Metro Line 2, the cutter type is selected according to the characteristics of soft soils and large-diameter piles. The angle of shell cutter is designed by the Advant Edge FEM finite element software, and the arrangement of the cutter layout is studied. The results show that for the shell cutter composed of double edges, zero back angle and negative front angle and combined with advance cutter and scraper, the layout of the concentric circle with three-section height difference and three-dimensional cutter is the most effective in cutting piles. Then the results are applied to the improvement of shield cutter head. The settlement of bridge deck is monitored during the shield driving process. The monitoring results show that the cumulative settlement of bridge deck in the cross-river section during shield grinding piles is only -3.09 mm, which has no obvious influence on the Fengqi bridge and river. The cutting steel bar is effective except that the cutter is worn on a few parts. This technology has been successfully applied to the grinding piles of Fengqi bridge of Hangzhou Metro Line 2, which may provide insights for the similar grinding pile projects.