水泥基固化剂固化南沙软土的力学及微观试验研究

Experimental Research of Mechanics and Microscopic on Nansha Soft Soil Reinforced with Cement-based Curing Agent

以普通硅酸盐水泥为基础,分别添加石灰、石膏、膨润土等外掺剂对广州南沙软土进行固化处理.通过直剪试验、无侧限抗压试验对固化土样进行了力学性能研究,分析了固化土体的内摩擦角、黏聚力、无侧限抗压强度随不同外掺剂掺入比及龄期的变化关系;通过扫描电子显微镜(SEM)研究了不同固化土样的微观结构特征.试验结果表明:与单掺水泥类似,添加不同外掺剂后土体的各个力学指标均随着外掺剂掺入比和龄期的增加而增大不同外掺剂对水泥加固淤泥效果的影响不尽相同,就后期强度而言石灰效果最佳,就早期强度而言石膏、膨润土效果都很好,膨润土相对更佳,且当强度要求一定时石膏和膨润土都能一定程度降低水泥使用量.这与固化后土体的微观结构有关.该研究成果可供类似研究和工程参考.

Direct shear test and unconfined compression test were conducted on soft soil at Nansha of Guangzhou blended with ordinary Portland cement and admixtures such as lime , gypsum and bentonite respectively to study its mechanical property and get the variation of reinforced soil＇s internal friction angle （IFA）, cohesion, unconfined compressive strength （UCS） according to the different mixing ratios or ages of the curing agents .Scanning electron microscope observation （ SEM ） was also applied to research the different microstructural characteristics of different reinforced soil .The results show that data trending is similar to the outcome when cement is blended in merely .Mechanical parameters of the reinforced silt in-crease when the mixing ratio or age increases .But different curing agents have different influences .Lime has the best effect on long-term strength .For early age strength , bentonite has the best reinforcement effect and gypsum takes second place .To get a certain strength , both gypsum and bentonite can reduce the consumption of cement at a certain degree .The research result has a certain reference to the similar research and engineering .