聚丙烯酰胺改性石灰固化吹填土固结特性研究

Experimental study on consolidation characteristics of polyacrylamide-modified lime-stabilized dredger fill

吹填土加固技术成为当前软基处理的一项技术难点。石灰等固化材料的掺加提升了吹填土的抗压、抗剪强度,但降低了其抗变形能力。通过添加不同掺量的聚丙烯酰胺,利用室内一维固结压缩试验探讨其对石灰固化吹填土的固结特性的影响,并对固结后的土样进行了压汞试验分析,探讨了微观孔隙特征与宏观变形特性的相关性。研究表明:聚丙烯酰胺可以有效改善石灰加固吹填土的抵抗变形能力,改善其脆性破坏的特点;聚丙烯酰胺掺加增强了石灰加固吹填土体的结构性特征,结构屈服应力较单一石灰添加提高了54%;聚丙烯酰胺的增加提高了石灰固化吹填土的固结系数,且掺加量越大,固结速率的提升幅度越大;聚丙烯酰胺、石灰的组合掺加可以改善吹填土固结后的孔径分布特征,相同石灰掺加量下,随着PAM含量的增加,加固土体的大直径孔隙的含量不断增多,渗透性增强,固结速率增大,微观孔隙特征与宏观变形特性保持了内在的一致性。

The technology of dredger fill treatment becomes one of the technical difficulties in soft soil foundation treatment. The compressive strength and shear strength of dredger fill can be improved by adding lime and other solidified materials,but the deformation performance will decline. The effect of different dosages of polyacrylamide on the consolidation behaviors of lime solidified dredger fill is discussed by indoor one-dimensional consolidation tests and mercury intrusion porosimetry. The test shows that the polyacrylamide can effectively improve the deformation capacity of the dredger fill cemented by lime, and make it close to the consolidation performance of the non-reinforced dredger fill. The presence of polyacrylamide can also increase by 54% of the structural yield stress than that of lime solo addition. The addition of polyacrylamide can increase the coefficient of consolidation of lime solidified dredger fill, and the additional proportion of polyacrylamide is larger, the consolidation rate of increase is greater. The pore-size distribution is rearranged as a result of the lime and PAM addition, which leads to large porosity and higher permeability. The microscopic parameters are in correlation with the macroscopic deformation behaviors in essence.