Shield cutter for cutting large diameter group piles in gravel stratum
The cutter is the main component of the shield for cutting and advancement. Suitable selection and design of cutter are essential in ensuring to the successful cutting of large diameter reinforced concrete group piles. Based on the Shenyang Metro Line 4 project,the cutters were selected based on the engineering characteristics of the shield crossing the gravel stratum and the need to cut large diameter reinforced concrete group piles. The software LS-DYNA was used to simulate the effect of shell cutters on cutting rebars with different blade widths,blade angles and rake angles. The results of analysis were applied to this project. The appropriateness of the cutter selection and design was validated by comparing the settlement variations of the existing tunnels. By analyzing the wear characteristics of the cutters and the discharge of the rebars after cutting,the cutting effect was evaluated,and then the cutters arrangement of the cutterhead was optimized. The results show that the shield cutting effect can be improved by using a panel and spoke composite right-angle cutterhead,and a double-sided blade shell cutter with rake angle of-45° and zero rear angle,5 mm blade width,90° blade angle. The deformation fluctuation of the existing tunnel during the shield pile cutting process is controlled within 1.1 mm. The maximum settlement of the existing tunnel after crossing is only 1.96 mm. This does not have any significant impact on the existing tunnel. When using shell cutters,the increasing number of 210 mm shell cutters is able to improve the cutting capacity of the cutter and reduce the risk of chipping,especially for spokes with only one leading cutter. The results of the cutter selection design are successfully applied to the Shenyang Metro Line 4 pile cutting project,which can serve as a reference for similar projects in the future.
shield tunneldirect cutting pileslarge diameter group pilescutter designsettlement monitoring
万方数据
维普
