地层中粉细砂在盾构壁后注浆中的再利用研究

Reuse of excavated fine sand for back grouting of shield tunnelling

南京长江隧道主要穿越的地层为粉细砂,这种地层具有良好的级配,如果开挖后直接排放易造成堆放环境问题,也造成了资源的浪费。为此,研究了开挖排放的粉细砂在盾构壁后注浆中的再利用的问题。通过考虑地层不均质性——土砂比,研究了各种渣土情况下的浆液性质的变化。结果表明,盾构开挖排放的粉细砂渣土能够满足盾构壁后注浆施工的要求,浆液配方应根据土砂比的变化,快速作出调整,以保证浆液的性质不发生较大的变化。

The stratum of Nanjing Yangtze River Tunnel is mainly fine sand,of which the grain composition is good.If the excavated fine sand is discharged directly,the environment near the piling position is easily polluted;and it is also resources waste without reuse.Based on the above consideration,the main subject of research is that how the discharged fine sand can be reused in the aspect of back grouting,and after the reuse of the fine sand,the back grouting recipe should be regulated in time with the change of grain compostion of excavated fine sand.The results show that the excavated fine sand can be reused in the back grouting substituted for the purchased sand,which can save money groatly.