盾构刀盘开口率对富水粉细砂层地表沉降的影响

Effect of Metro Shield Cutter-head Aperture Rate on Ground Surface Subsidence of Water-rich Silty Fine Sand Layer

针对盾构机在富水粉细砂层中修建地铁引起的地表沉降问题,基于地表沉降理论,以太原地铁2号线某富水粉细砂层的盾构掘进区间段为研究对象,模拟不同开口率的刀盘对地表沉降的影响。结果表明,土压平衡式盾构机采用大开口率刀盘更适用于掘进富水粉细砂层,选用50%开口率的刀盘的土压平衡盾构机可成功将地表沉降控制在2 cm以内;推导出的经验公式适用于盾构机掘进富水粉细砂层的地表沉降计算;根据盾构实测出土量最终确定刀盘开口率为51%的盾构机更适合掘进太原地区富水粉细砂层。

Aiming at the problems of surface settlement due to metro construction in water-rich silty sand layer by shield machine,and based on the theoretical analysis of surface subsidence,the shield tunneling section in water-rich fine sand layer on Taiyuan metro Line 2 is taken as the research object,the influences of different aperture rate of the cutter-head on the ground surface subsidence are simulated.The research shows that the cutter-head with large aperture rate adopted in earth pressure balanced(EPB)shield machine is more suitable for driving in the water-rich silty fine sand layer.When the EPB shield machine select the 50%aperture rate cutter-head in the construction,the ground surface settlement could be successfully controlled within 2 cm,and the empirical formula obtained could be used to calculate the ground surface settlement of shield tunneling in water-rich silty fine sand layer.According to the measured excavation volume of shield tunneling,the cutter-head with 51%aperture rate is proved to be more suitable for shield tunneling in the water-rich silty fine sand layer of Taiyuan City.