有机硅改性路基土体渗透性变化及微观结构分析

Analysis of permeability change and microstructure of organic silicon modified roadbed soil

为避免公路受地下水侵蚀造成路基病害,本文采用有机硅疏水材料作为新型路基隔水层材料,以粉质黏土为试验对象,研究喷洒疏水材料后的土体其隔水效果及内部微观结构的变化。首先,通过渗透试验研究土体渗透性能变化规律,总结有机硅疏水材料作用方式;然后,采用接触角实验表征土体表面疏水性变化;最后,利用图像分析手段研究改性土体内部孔隙结构的改变。结果表明:路基土体渗透系数及土体表面接触角均随着有机硅疏水材料单位面积用量的增加而逐渐减小,双层喷洒、单位面积用量为100 g/m^(2)时其渗透系数最低,与素土相比下降95.43%。喷洒疏水材料后,土体表面接触角均大于105°,表现出较强的疏水性。有机硅疏水材料对于土体微观孔隙结构变化具有重要影响,土体内部大孔隙转变为小孔隙是其抗渗性能增强的主要原因。

In order to avoid subgrade diseases caused by groundwater erosion on highway,the organic silicon hydrophobic material was used as a new type of water resisting layer material to study the water barrier effect and the variation of its internal microstructure of soil,and the silty clay was the test object in this process.Firstly,the variation rules of soil permeability performance were studied through penetration test,and the action mode of hydrophobic material was summarized.Secondly,the contact angle test was used to characterize the hydrophobicity change of the soil surface.Finally the variation of the pore structure inside the soil was studied by means of image analysis.The results show that the permeability coefficient and the contact angle of the soil gradually decrease with the increase of the amount of the hydrophobic material per unit area.When the double-layer arrangement and the amount of the hydrophobic material is 100 g/m^(2),the permeability coefficient is the lowest,which is 95.43%lower than that of the common soil.The contact angles of the soil modified with hydrophobic materials are all greater than 105°,the soil surface shows strong hydrophobicity.The hydrophobic material has an important influence on the microscopic pore structure of the soil.The transformation of large pores into small pores is an important reason for the enhancement of its impermeability.