土压平衡盾构加气排水防喷涌技术研究

针对地下水丰富、节理裂隙发育、渗透系数大和气密性差的地层,常规的土压平衡盾构掘进易发生喷涌现象,导致地表沉降变形大、施工效率低。本文依托兰州地铁1号线、2号线土压平衡盾构施工项目,建立土压平衡盾构舱内压力传递模型,对土压平衡盾构舱内压力传递原理和加气排水防喷涌机理进行研究,提出土压平衡盾构"加气排水"掘进施工方法;通过土压控制和掘进舱压控制实现了"加气排水"掘进施工的过程控制;应用地质雷达扫描和注浆加固技术解决了地层疏松、空腔等缺陷。

Research on the Technology of Aeration Drainage and Spew Prevention for Earth Pressure Balance Shield

For the stratum with rich groundwater,developed joints and fissures,and high permeability coefficient and poor air tightness,the conventional earth pressure balance shield tunneling is prone to the phenomenon of spewing,leading to large ground surface settlement and low construction efficiency.Based on the construction project of earth pressure balance shield of Lanzhou Metro Line 1 and Line 2,a tunneling construction method of"aerated drainage"for earth pressure balance shield was proposed by establishing the pressure transfer model in the tank of earth pressure balance shield and studying the mechanism of aerated drainage and anti-spew.The process control of"aerated drainage"tunneling was realized from the aspects of soil pressure control and tunneling cabin pressure control.Finally,the defects such as loose soil and cavity were solved by using geological radar scanning and grouting reinforcement technology.