含有机质土渗透特性的研究

Study on permeability characteristics of organic soil

为了研究含有机质土的渗透特性,通过在蒙脱石、伊利石和高岭土中添加泥炭,分别配置了6组不同有机质含量的矿质土样。利用固结-渗透联合试验的结果,分析了固结压力、孔隙比、干密度、有机质含量及矿物成分对含有机质土渗透特性的影响。试验结果表明:随着固结压力、干密度、有机质含量的增加以及孔隙比的减小,渗透系数整体呈下降的规律。其关系可分为2个阶段:显著下降阶段及平缓下降阶段。在显著下降阶段,渗透系数随固结压力的变化幅度可达37%~78%;干密度、有机质含量提高1%,孔隙比降低1%,渗透系数分别降低1%~4%、2%~6%及1%~11%。在平缓下降阶段,渗透系数随固结压力的变化幅度为8%~11%;干密度、有机质含量提高1%,孔隙比降低1%,渗透系数分别降低0.2%~0.8%、0.5%~0.6%及0.9%~1.8%。矿物成分对土渗透特性的影响较大,3种矿质土的渗透系数由大到小为伊利石>高岭土>蒙脱石。

In order to study the permeability characteristics of organic soil,six mineral soil samples with different organic matter contents were prepared by adding peat to montmorillonite,illite and kaolin.The effects of consolidation pressure,void ratio,dry density,organic matter content and mineral composition on the permeability characteristics of organic soil were analyzed by using the results of the consolidation-permeability combined experiment.The experimental results show that with the increase of consolidation pressure,dry density,organic matter content and the decrease of void ratio,the overall permeability coefficient shows a decreasing trend.The relationship can be divided into two stages:A significant decline stage and a gentle decline stage.During the significant decline stage,the variation amplitude of permeability coefficient with consolidation pressure can reach 37%to 78%.For 1%increase in dry density and organic matter content,and for 1%decrease in void ratio,permeability coefficient decreases by 1%to 4%,2%to 6%,and 1%to 11%,respectively.During the gentle decline stage,the variation range of permeability coefficient with consolidation pressure is between 8%and 11%.For 1%increase in dry density and organic matter content,and for 1%decrease in void ratio,permeability coefficient decreases by 0.2%to 0.8%,0.5%to 0.6%,and 0.9%to 1.8%,respectively.The mineral composition has a significant impact on the permeability characteristics of soil.The permeability coefficients of the three types of mineral soils vary from large to small:Illite>kaolin>montmorillonite.