不同浓度PVA对滨海吹填土理化性状的影响

吹填土来源于海底淤泥,含盐量高,土质黏紧,无法直接用于生态建设,为改善吹填土结构,提高吹填土的脱盐效率,提升吹填土生态利用价值,利用新型土壤改良剂——高分子聚合物PVA,通过室内土柱淋洗试验,研究不同浓度的PVA溶液对天津滨海吹填土透水性、水稳性团聚体、含水量、电导率、水溶性盐基离子和pH值变化的影响。结果表明:0.2%、0.5%和1.0%3个PVA浓度下的吹填土淋出液电导率降至1 dS/m以下,历时分别为350、361 h和400 h,未施用处理则用时587 h;淋洗412 h后淋出液总体积分别为1.69、1.76、1.28 L,未施用处理为0.47 L,较未施用分别增加了259.57%、274.47%、172.34%;0.25 mm以上的土壤水稳性团聚体含量较未施用处理的22.40%分别增加了37.9、42.6、46.9个百分点;淋洗412 h后吹填土全盐量均小于9.674 g/kg,pH值较处理前有所升高。

Effect of PVA by Different Concentration on Physical and Chemical Properties of Dredge Fill in Coastal Region

Dredge fill originally came from sludge beyond the seabed,it was impossible to be applied to ecological construction directly due to its high salinity and soil texture.To improve the structure and desalting efficiency of dredge fill and enhance the ecological value of that soil in use,a kind of new soil conditioner high molecular compound called PVA was applied.Effects of PVA by different concentration on the variation of water permeability,water stable aggregate,moisture,EC,water soluble base ion and pH of hydraulic fill were studied by soil column leaching test in the laboratory in this paper.The results showed that when the concentration of PVA were 0.2%,0.5%and 1.0%,it cost 350,361 and 400 h while EC of leachate decreased below 1 dS/m,while soil without application used 587 h;When leaching last for 412 h,the total volume of leachate were 1.69、1.76 and 1.28 L,compared to soil without application of which leachate volume was 0.47 L,were increased by 259.57%、274.47%and 172.34%.Content of water stable aggregate which is larger than 0.25 mm were increased by 37.9、42.6 and 46.9 percentage point compared to 22.4% from soil without application.soil salinity was all less than 9.674 g/kg in 412 h of leaching,pH value was higher than original soil.