阳离子聚丙烯酰胺改良弱膨胀土试验研究

Experimental study on improved weakly expansive soil of cationic polyacrylamide

为探究环保材料阳离子聚丙烯酰胺(CPAM)改良膨胀土的实际工程效果,通过一系列室内试验对改良土特性进行研究。结果表明:随着CPAM的掺入,土的液限和塑性指数逐渐降低,塑限逐渐提高,自由膨胀率和有荷膨胀率逐渐降低;改良土在水中崩解性较小,水稳性能更加优越;抗剪强度随着掺量的增加而提高,土的黏聚力先增大后减小,内摩擦角逐渐增大,最佳掺量为0.6%;扫描电镜(SEM)显示经CPAM改良后膨胀土弯曲起皱的薄片数减少,叠聚体排列方式由面-面转为边-角或边-面-角,形成了网架结构,提升了土体强度和空间稳定性,研究结果可为工程施工设计提供参考。

In order to investigate the actual engineering effect of cationic polyacrylamide(CPAM),an environmentally friendly material,and improve swelling soil,a series of indoor tests were conducted to investigate the characteristics of the improved soil.The results show that with the addition of improver,the liquid limit and plasticity index of soil decrease gradually,the plastic limit increases gradually,and the free swelling ratio and loaded swelling ratio decrease gradually.The improved soil has less disintegrating property and better water stability.The shear strength increases with the increase of the content,the cohesion of the soil increases first and then decreases,and the Angle of internal friction increases gradually.The optimal content is 0.6%.Scanning electron micrograph(SEM)showed that after CPAM improvement,the number of curved and wrinkled sections of the expansive soil was reduced,and the arrangement of the stacking polymer changed from face-face to side-angle or side-face-angle,forming a mesh structure and improving the strength and spatial stability of the soil.The research results can provide reference for engineering construction and design.