聚丙烯酸钠改性红黏土工程特性试验研究

Experimental study on engineering properties of red clay modified by sodium polyacrylate

为研究聚丙烯酸钠改性红黏土的工程特性,利用聚丙烯酸钠对柳州重塑红黏土进行固化处理,开展变水头渗透试验和三轴剪切试验,分析改性红黏土的渗透特性和力学性能,确定聚丙烯酸钠的最适掺量,并通过对最适改性土开展崩解试验和扫描电镜试验,确定改性红黏土的抗崩解性能,揭示聚丙烯酸钠改性红黏土的微观作用机理。结果表明:随聚丙烯酸钠掺量的增加,改性土的渗透系数呈现逐步下降的趋势,并在达到3%后逐渐趋于稳定,此时渗透系数为8.1379×10^(-7)cm/s,相对素红黏土降低了90.78%;而改性红黏土的抗剪强度呈现先增大后减小的趋势,并在2%时达到峰值,相对素红黏土提高了394.21%。综上确定聚丙烯酸钠的最适掺量为3%,此掺量下改性土的抗崩解性能提高了42.86%,土颗粒间的孔隙被聚合物链所填充,碎散的颗粒状红黏土变为连续状,排列结构与致密程度均优于素红黏土。经聚丙烯酸钠改性后,红黏土的防渗性能、力学性能与抗崩解性均存在明显提高,可以为实际工程提供理论指导。

To study the engineering properties of red clay modified by sodium polyacrylate,the Liuzhou remodeled red clay cured by sodium polyacrylate was selected for the permeability test with variable head and triaxial shear test to analyze the permeability and mechanical properties of the modified red clay and to determine the optimum amount of sodium polyacrylate.The disintegration resistance and microscopic mechanism of the modified red clay were determined by the disintegration test and scanning electron microscope test,respectively.The results show that the permeability coefficient of the modified soil decreases gradually with the increase of sodium polyacrylate,and gradually stabilizes after reaching 3%with the permeability coefficient of 8.1379×10^(-7) cm/s,90.78%lower than that of the plain soil.In contrast,the shear strength of the modified red clay shows an increasing trend firstly,then decreases,and then keeps stable at at 2%,which is 394.21%higher than that of the plain soil.The optimal dosage is 3%,and in such situation,the anti-disintegration performance of the modified soil is improved by 42.86%.The pores between the soil particles filled by polymer chains lead to the continuous fragmented granular red clay.The arrangement structure and denseness are better than those of the plain red clay.The impermeability,mechanical properties,and disintegration resistance of the red clay modified by sodium polyacrylate are significantly improved.This study can provide theoretical information for the practical engineering.