地铁盾构刀盘改造及掘进性能对比研究

为更好地适应富水中砂地层的盾构施工,对土压平衡式盾构机原有刀盘结构、刀具布置等进行了改造。刀盘开口率由28%增加到40%;在刀盘中间增加了鱼尾刀;增加了两根长度为50 cm、直径为15 cm的主动搅拌棒;对富水中砂渣土进行了改良。对比改造前后的刀盘掘进性能发现改造后的刀盘掘进性能得到明显提升,具体表现在:盾构机掘进速度提升了4倍,刀盘平均扭矩降低了20%,土压波动范围变小,渣土温度降低了40℃,地面沉降亦得到了明显改善。

Comparative Study on the Modification of Shield Cutter-head and the Excavation Performance

The original cutter-head structure and cutter arrangement are reformed to adapt to the shield construction in medium sand strata with rich water.The cutter-head opening ratio is increased from 28％ to 40％,and a fish cutter is added in the middle of the cutter-head,two extra stir bars with the length of 50 cm and the diameter of 15 cm are added in the cutter-head,the flow plasticity of muck with medium sand and water is also improved.By comparing the performances of the cutter-head before and after the modification,it is clear that the cutter-head performance is improved obviously,the excavation speed has increased 4 times,while the cutter-head torque decreased by 20％ on average.In addition,the range of soil pressure fluctuation becomes smaller,the temperature drop of muck is more than 40 ℃,and the ground settlement is also improved significantly.