盾构直接切削桩基施工关键技术

为解决盾构刀盘在切削桩基过程中出现的刀盘刀具异常损坏、刀盘卡死及掘进效率低下等问题，依托以色列特拉维夫轻轨红线项目，采用刀盘切削桩基实体模型方法，通过模拟不同刀具布置和多种掘进工况，分析掘进参数及刀具布置对桩基破坏形态、刀盘破坏形态的影响规律。研究结果表明，在盾构刀盘切削桩基过程中，存在最佳切削推进速度（3~5 mm/min）、刀盘转速（1.0~1.2 r/min）和最佳转矩（3 300~4 300 kN?m）等，且滚刀和切刀的数量对于切削桩基有着一定的影响。现场实际掘进和监测结果表明，利用该实验结果合理地调整相关参数，在轻轨项目中盾构切削桩基过程未出现卡机、刀盘损坏等现象，取得了良好的效果。

Key Technologies of Shield Direct Cutting Pile Foundation

Obstacles such as pile foundations are frequently encountered during shield boring. In such case, the cutters and cutterhead of the shield would be jammed or even damaged, and the boring efficiency is probably low. As a result, a entity model of cutterhead direct cutting pile foundation of Red Line of Tel Aviv LRT project is established to simulate different layouts of cutting tools and different boring conditions, and analyze the influencing laws of shield boring parameters and cutting tool layout mode on failure mode of pile foundations and shield cutterhead. The analytical results show that during shield cutterhead cutting pile foundation, the optimum boring parameters of advancing rate, cutterhead rotation speed and torque are 3-5 mm/min, 1.0-1.2 r/min and 3 300-4 300 kN?m, respectively; and the number of disc cutter and cutting bit have some influence on the cutting of the pile foundations. The practice of pile foundation cutting by shield and the monitoring results demonstrate good effects, such as no cutterhead jamming and damage, have been achieved during shield cutting pile foundation by rationally adjusting relative parameters.