砂卵石地层泥水平衡盾构隧道掘进参数控制

砂卵石地层具有地层结构松散、孔隙率大、整体强度低等特点,在此地层中进行盾构施工,合理设置掘进参数至关重要。以兰州地铁1号线迎门滩—马滩区间隧道砂卵石地层泥水平衡盾构施工为依托,研究了砂卵石地层泥水平衡盾构掘进参数。现场监测结果表明,加大盾构总推力能够适当提高掘进速度,而加快刀盘转速却不能达到这一效果。采用FLAC 3D有限元软件数值模拟了不同支护压力和注浆压力下盾构隧道掘进过程。结果表明:掌子面支护压力应与掌子面土压力相匹配,同步注浆压力应与掌子面原位应力基本一致或略高。

Control of Tunnel Driving Parameters of Slurry Balance Shield in Sandy Gravel Stratum

The sandy gravel stratum has the characteristics of loose stratum structure,large porosity and low overall strength.It is necessary to select proper driving parameters for shield tunneling in this stratum.Based on the construction of slurry balance shield in sandy gravel stratum at the interval tunnel between Yingmentan station and Matan station of Lanzhou metro line 1,the driving parameters of slurry balance shield in sandy gravel stratum were studied.Field monitoring results show that increasing the total thrust of shield can properly improve the driving speed,but accelerating the speed of cutter head can not achieve this effect.The FLAC 3D finite element software was used to simulate the shield driving process under different supporting pressures and grouting pressures.The results show that the support pressure of tunnel face should match the soil pressure of tunnel face,and the synchronous grouting pressure should be basically consistent with or slightly higher than the in-situ stress of tunnel face.