冻融循环对全尾砂固结体强度的影响

为探究冻融循环对全尾砂固结体强度的影响,以不同冻结温度下的固结体为研究对象,采用冻融循环、单轴压缩和扫描电镜(SEM)等试验方法,研究了不同养护龄期及冻结温度下的固结体强度变化规律,分析了不同冻融循环次数及冻结温度下固结体内部水化产物及微观结构特征演化规律。结果表明:同一冻结温度、不同养护龄期下,固结体强度随冻融次数增加呈先增加后减少的趋势,基本遵循二次幂函数的定量关系;同一养护龄期、不同冻结温度下,固结体强度随冻结温度的降低呈下降趋势;相同冻结温度和养护龄期下,随冻融次数增加,固结体内部结构呈稀疏→致密→松散的发展趋势;相同养护龄期和冻融循环次数下,冻结温度越低,C-S-H凝胶和晶体状的钙矾石(AFt)等水化产物的生成量越少,固结体内部结构越稀疏、松散。

Effect of Freeze-thaw Cycle on the Intensity of Consolidated Full Tailings

In order to explore the impact of freeze-thaw cycles on the strength of the consolidated tailings， freeze-thaw cycles， uniaxial compression and scanning electron microscopy （SEM） were used to study the consolidated tailings at different freezing temperatures. The variation of consolidation strength under different curing ages and freezing temperatures was studied， and the evolution rules of hydration products and microstructure characteristics within consolidation mass under different freezing and thawing cycles and freezing temperatures were analyzed. The results showed that the strength of consolidation increases first and then decreases with the increase of freezing-thawing times at the same freezing temperature and different curing ages， which basically follows the quantitative relationship of quadratic power function. At the same curing age， the strength of the consolidated mass is decreased with the decrease of freezing temperature. With the increase of freeze-thaw cycles， the internal structure of the consolidated mass shows as sparse， dense and loose under the same curing age and freezing temperature. Under the same curing age and freeze-thaw cycles， the lower the freezing temperature is， the less the amount of hydration products such as C-S-H gel and crystal ettringite （AFt） are produced， and the sparser and looser the internal structure of the consolidated mass displays.