水泥稳定盾构渣土的收缩性能研究

Research on Shrinkage Properties of Cement-stabilized Shield Soils

针对土压平衡(earth pressure balance,EPB)盾构渣土的资源化再利用问题,开展水泥稳定EPB盾构渣土作为路用材料的收缩性能研究,主要通过干缩试验及温缩试验进行评价。结果表明,EPB盾构渣土的干缩系数在前31天变化明显,温缩系数则随着温度的升高呈现波动性上升趋势;水泥掺量的增加不仅会影响EPB盾构渣土体积对温度、水分变化的敏感程度,还会进一步增强温度对体积的影响;与常用的水泥稳定碎石相比,EPB盾构渣土受掘进工艺影响缺少大粒径骨料的嵌挤作用,因而收缩性能较差。因此,在EPB盾构渣土施工过程中不仅需要严格控制水泥用量,还应掺入些许骨料调整其级配。

Aiming at the problem of the resource recycle of earth pressure balance(EPB)shield soils,the shrinkage properties of EPB shield soils were evaluated mainly through drying shrinkage tests and temperature shrinkage tests.The results suggested that the dry shrinkage coefficient of EPB shield soils changed significantly in the first 31 days,while the temperature shrinkage coefficient showed a fluctuating upward trend with the increase of temperature;the increase of cement content will not only affect the sensitivity of the volume of EPB shield soils to changes in temperature and water,but also further enhance the influence of temperature on volume;compared with common cement-stabilized crushed stone,EPB shield soils lacks the embedding effect of large-sized aggregates due to the influence of the tunneling process,resulting in poor shrinkage performance.Therefore,in the construction process of EPB shield soils,not only the cement dosage should be strictly controlled,but also a little aggregate should be mixed to adjust its gradation.