粉煤灰-镁渣改良超盐渍土的工程性质研究

Experimental Study on Mechanics Characteristics of Solidified Hypersaline Soil with Fly Ash and Magnesium Slag

利用宁夏平罗县的超盐渍土,分别掺入20%、25%、30%粉煤灰和镁渣替代6%、8%、10%的粉煤灰进行固化处理。通过7 d、28 d龄期的三轴试验表明,相同粉煤灰掺量的超盐渍土的黏聚力随着镁渣掺量的增加呈先减小后增加的趋势;7 d龄期的试件,相同粉煤灰掺量的超盐渍土的摩擦角随着镁渣掺量的增加呈先增加后减小的趋势。28 d龄期的试件,相同粉煤灰掺量的超盐渍土的摩擦角随着镁渣掺量的增加基本呈现增加的趋势。粉煤灰、镁渣固化的各组超盐渍土,随着龄期的变化,黏聚力和摩擦角的平均变化幅度在4.2%以内,各组试样的抗剪强度变化不明显,粉煤灰、镁渣加固盐渍土的机理主要表现为物理加固,在工程中利用粉煤灰、镁渣固化超盐渍土时,只需考虑两者的物理加固作用。

The shear strength of solidified hypersaline soil was studied, in which the fly ash phase was partially replaced by magnesium slag.Ningxia Pingluo county hypersaline soil, were mixed with 20%, 25%, 30%fly ash and 6%, 8%, 10%magnesium slag for solidification, shear strength of the 7 d and 28 d age investigated by triaxi-al test, respectively.The results show that when the dosage of fly ash is same, the cohesion increased and then de-creased with the content of magnesium slag for 7 d age, the friction angle decreased and then increased with the content of magnesium slag and the friction angle shows an increasing trend basically with the content of magnesium slag for 28 d age.It is concluded that solidified hypersaline soil with fly ash and magnesium slag is mainly physical reinforcement because the average variations of the cohesion and the friction angle within 4.2%and the change of shear strength is unobvious for all groups.Some advices are also proposed for the design and construction of solidifi-cation of hypersaline soil by fly ash and magnesium slag, that is, physical reinforcement is mainly considered.