水泥窑灰改性黄土的湿陷性和强度特性研究

A study of the collapsibility and strength property of loess stabilized by cement kiln ash

对水泥窑灰改性黄土进行压缩、湿陷和无侧限抗压强度试验,研究水泥窑灰对黄土压缩性、湿陷性和强度特性的影响。同时进行压汞试验和扫描电镜试验,分析改性前后黄土的孔隙分布特征、颗粒接触形态和结构的变化,探索微观特征与宏观性质之间的关系。结果表明,向黄土中添加水泥窑灰能够显著降低其压缩性和湿陷性,使黄土由中压缩性降低为低压缩性,由中等湿陷降低到轻微湿陷乃至湿陷性消失,同时抗剪强度得到显著提高。微观试验结果表明,水泥窑灰改性后的团聚体间的孔隙消失,转化成为团聚体内的孔隙,且总孔隙比降低,土体更加密实;颗粒间连接作用增强,土体结构更加稳定。

Compressive test,collapse test and unconfined compressive strength test were conducted to investigate the compressibility,collapsibility and strength property of loess stabilized by cement kiln ash.Mercury intrusion porosimetry test and scanning electron microscope test were also performed to analyze the changes in the pore distribution characteristics,the contact form of soil particles and the structure of compacted samples for the stabilized loess.The results indicate that adding cement kiln ash to loess can make both the compressibility and collapsibility reduce prominently.The compressibility is reduced from moderate to low,and the collapsibility is reduced from moderate to mild and disappears at last.Furthermore,the strength property is enhanced obviously.The microscopic test results show that inter-aggregate pores in the stabilized loss sample disappear and change into inter-aggregate pores with the increasing cement kiln ash,and the total void ratio is also reduced.The connection between particle is enhanced,making the soil structure more stable.