全断面砂层土压平衡盾构施工关键技术研究

Study on Key Technologies of Earth Pressure Balance Shield Construction in Full-section Sand Layer

土压平衡盾构在全断面砂层施工时,通常会出现刀盘和刀具磨损严重、推力和扭矩较大、掘进困难以及沉降过大等问题。针对全断面砂层土压平衡盾构施工,对渣土改良、刀盘和刀具以及泡沫系统改造等关键技术进行研究和工程实践,并对实施效果进行评价。实践证明,膨润土泥浆和泡沫对砂层渣土改良效果及地表沉降控制效果显著;配合泡沫系统改造,盾构掘进过程中推力和扭矩减小,掘进速度提高;刀盘和刀具改造后,磨损程度明显降低。

When the earth pressure balance shield is used in the construction of the full-section sand layer,problems such as severe damage to the cutter head and the cutter,large thrust and torque,difficulty in boring and excessive settlement are often caused.For the construction of full-section sand layer soil pressure balance shield,the key technologies of construction are utilized such as improving the muck,transforming the cutter head,cutter and foam system,and the effect of construction key technology is evaluated.The results show that the improvement effect of bentonite mud and foam on sand layer slag is significant,and at the same time,with the foam system transformation,the thrust and torque are reduced during the tunneling process,and the tunneling speed is improved.After the modification of cutter head and cutter,the wear degree of cutter head and cutter is obviously reduced.