水泥偏高岭土复合稳定粉砂土渗透特性试验研究

水泥稳定粉砂土抗渗性能受粉砂土自身渗透性能、水泥用量、水灰比等因素影响显著，如何在提升其抗渗性能的同时降低水泥用量是提升工程经济效益的关键。通过开展不同水泥偏高岭土掺比、初始用水量、水泥偏高岭土总掺量以及养护龄期条件下的室内渗透试验，研究了上述因素对水泥偏高岭土复合稳定粉砂土抗渗性能的影响规律，探讨了上述因素及无侧限抗压强度与渗透系数之间的经验关系。结果表明：水泥与偏高岭土掺比为5:1时，水泥偏高岭土复合稳定粉砂土抗渗性能最佳，且该掺比不随水泥偏高岭土总掺量的改变而变化；水泥偏高岭土复合稳定粉砂土渗透系数随初始用水量增加呈非线性递增，随水泥偏高岭土总掺量增加和养护龄期发展呈先快后慢降低；基于试验结果归纳提出了4个关于初始用水量、水泥偏高岭土总掺量、养护龄期和无侧限抗压强度的水泥偏高岭土复合稳定粉砂土渗透系数经验模型。研究成果可为水泥稳定粉砂土抗渗性能提升提供理论参考与借鉴。

Permeability characteristics of cemented silty sand improved by metakaolin

The impermeability of cement-stabilized silty sand is significantly affected by the permeability of itself, the dosage of cement, the water-cement ratio, and other factors. How to improve the impermeability of cement-stabilized silty sand while reducing cement dosage is the key to improving the economic benefit of the project. In this study, a series of indoor permeability tests was conducted on cement-metakaolin stabilized silty sands with different cement-metakaolin ratios, initial water consumption, total cement-metakaolin contents, and curing ages. The influence of the above factors on the impermeability of cement-metakaolin stabilized silty sands were investigated, and the empirical relationships between the permeability coefficient and these factors as well as their corresponding unconfined compressive strength were discussed. The results showed that the impermeability of cement-metakaolin stabilized silty sands achieved the optimization when the ratio of cement to metakaolin was 5:1, and this mixing ratio did not change with the total cement-metakaolin content used in silty sand stabilization. The permeability coefficient of cement-metakaolin stabilized silty sands increased nonlinearly with the initial water consumption and decreased rapidly first and then slowly with the increase of the total cement-metakaolin content and curing age. Four empirical formulas for the permeability coefficient of cement-metakaolin stabilized silty sands were summarized with respect to initial water consumption, total cement-metakaolin content, curing age, and unconfined compressive strength. The results of this study can provide a theoretical reference for improving the impermeability of cement-stabilized silty sands.