氯盐和冻融耦合下水泥土的强度和破坏特征

为了研究氯盐侵蚀和冻融循环耦合下水泥土无侧限抗压强度和破坏特征， 进行了不同浓度氯化钠溶液下的水泥土冻融循环试验， 得到了冻融前后的冻融腐蚀因子、 体积变化率和变形模量， 分析了微观结构特征。结果表明： 在氯盐侵蚀和冻融循环耦合下， 水泥土的无侧限抗压强度、 冻融腐蚀因子均随着冻融循环次数的增加而呈现下降趋势； 氯盐浓度越高， 水泥土的无侧限抗压强度、 冻融腐蚀因子下降的幅度越大。随着冻融循环次数的增加， 在同种浓度溶液中， 水泥土的体积变化率增大， 变形模量减小； 氯盐浓度增大， 水泥土体积膨胀变大， 内部结构松散， 抵抗变形的能力减弱。相同冻融循环次数下， 氯盐溶液产生的损伤要大于清水中的损伤， 随着氯盐溶液浓度的增加， 水泥土内部微观结构损伤越严重。

Strength and failure characteristics of soil-cement under coupling of chloride salt and freeze-thaw cycles

In order to study the unconfined compressive strength and failure characteristics of soil-cement under the coupling of chloride salt erosion and freeze-thaw cycles， the freeze-thaw cycle test of soil-cement with different concentrations of sodium chloride solution was carried out， and the freeze-thaw corrosion factor， volume change rate and modulus of deformation before and after freeze-thaw were obtained. The damage amount and microstructure characteristics were analyzed. It is found that the unconfined compressive strength and freeze-thaw corrosion factors of soil-cement under the coupling of chloride salt and freeze-thaw cycles decrease with increasing freeze-thaw cycles， and as the concentration of chloride salt increases gradually， the unconfined compressive strength and freeze-thaw corrosion factor of soil-cement decrease rapidly. In a same concentration solution， the volume change rate of soil-cement increases with increasing the number of freeze-thaw cycles， but the deformation modulus decreases with increasing the number of freeze-thaw cycles. As the concentration of chloride solution increases， the volume expansion of soil-cement increases， which results in a weaker internal structure and a weaker resistance to deformation. Under the same number of freeze-thaw cycles， the damage caused by sodium chloride solution is greater than that in specimen from clear water. As the concentration of sodium chloride solution increases， the damage of microstructure inside soil-cement becomes more serious.