Wettability And Microcosmic Characteristics Of Lignin Modified Loess

Overhead pores,weak cementation and rich in soluble salts are common characteristics of loess.Wettability and capillary water rise of loess affect soil structure,foundation strength,soil water content and other important properties of loess,and are important influencing factors for engineering construction.In this paper,the variation law of loess contact Angle and capillary water rising height with lignin content was obtained by laboratory test,contact Angle test and semi-permeable partition test.Through scanning electron microscope experiment,particle size analysis test and soil charge test,the changes of loess microstructure after adding lignin were studied from the microscopic point of view,as well as the reasons for the changes of wettability and capillary water rise height of the improved loess.The main research results are as follows:(1)The influence of wood content on loess wettability and capillary water rising height was revealed.With the increase of lignin content,the contact Angle of modified loess increased firstly and then decreased,and the contact Angle of loess with the addition of lignin was greater than that of natural loess.When the wood content was 2%,the wettability of loess was the weakest.(2)When the lignin content is more than 1%,with the increase of lignin content of the capillary water rising height increase with the decrease of the first,and after joining lignin modified loess of the capillary water rise height is less than the height of the capillary water rise,of natural loess when the lignin content is 2% minimum capillary water rising height,ratio of lignin content is the best at this time.(3)The effects of lignin on wettability and capillary water rise height were analyzed by microcosmic experiments.Lignin in loess reduces the pore area and increases the distribution of micro pores and small pores through the formation of cements between pores,thus reducing the wettability of loess.(4)Adding lignin to the loess can reduce the content of clay particles in the soil,reduce the fluidity of loess channels,and reduce the rise height of capillary water.(5)The increase of lignin increases the thickness of the bound water film in the soil,effectively reduces the effective pore radius,and improves the bond strength between the clay minerals and the particle skeleton.