西安地铁富水密实性砂层盾构带压换刀技术

Technologies for Shield Cutting Tool Replacement under Hyperbaric Condition in Water-rich and Compact Sandy Stratum of Xi'an Metro

为了解决西安地铁土压平衡盾构在富水密实性砂层中带压换刀所面临的土舱不易保压、作业人员进出舱气压控制难和舱内换刀安全风险高等技术难题,对带压进舱换刀技术开展了研究,通过工程实践总结出如下操作要点:1)通过工作压力计算,采取掌子面封闭、保压试验等技术措施使土舱压力趋于稳定,保证土舱压力满足要求;2)人员进舱后以10 kPa/min速率进行加压,人员出舱前以10 kPa/min速率分4个阶段逐渐减压;3)舱内换刀应制定周密的施工计划,刀盘分3次转动完成刀具更换。结果表明,通过以上控制技术,可以满足西安地铁富水密实性砂层盾构带压换刀施工要求。

The cutting tool replacement of earth pressure balance（EPB） shield used in Xi ＇an Metro has many difficulties,i.e.difficult pressure maintaining of earth chamber,difficult pressure control of earth chamber and high risk.As a result,technologies for shield cutting toll replacement under hyperbaric condition are studied.Key operation points are summarized as follows：1） The pressure of earth chamber becomes stable by carrying out tunnel face closing and pressure maintaining test.2） Increasing the air pressure with rate of 10 k Pa/min after the working personnel entering the chamber,and reducing the air pressure gradually in four phases with rate of 10 k Pa/min before the working personnel leaving the chamber.3） A detailed construction plan should be made before replacing the cutting tools;and then the cutterhead needs to roll by 3 times to complete cutting tool replacement.The results show that it can meet the construction requirements of shield cutting tool replacement under hyperbaric condition in water-rich and compact sandy stratum of Xi＇an Metro by adopting the above-mentioned technologies.