Abstract: This paper dealeds with the study on the micro-mechanism of CN2000B waterproofing coating.The microstructure of motor,waterproofing coating and permeability layer was obtained through scanning electron microscopy (SEM).Their main elements were determined and their relative weights(percentage) were calculated with X-ray energy dispersive analysis (EDAX).The test result was compared.The depth penetrated through mortar was deduced form the variations of elements content in different depth.The results of this study showed that the depth increased with curing time,and the value reached 29.14 mm at the age of 28 d.This study was applied to treatment of tunnel seepage on Shimen-Jishou section of Jiaozuo-Liuzhou railway.It can also be used for reference to treatment of the seepage on transportation railway tunnel.

Key words: waterproofing mechanism, waterproofing material of CN2000B, capillary crystalline type, penetration depth, scanning electron micorscopy (SEM), railway tunnel, treatment of the seepage