Research On Vapor Transportion Characteristics And Optimal Design Of Drainage In Red Clay Subgrade

Subgrade moisture migration mainly include some types that capillary action, embankment seepage caused by surface runoff generated by rainfall and high water level, and temperature water vapor changing generated by sunshine . The internal soil water content and pore water pressure will changes do to the effect of crack seepage, capillary action, and the temperature fields, correspondingly reducing soil strength, and finally soil come into subsidence and deformation , causing a series washout to subgrade .As is concerned, this page mainly do research on gleization mechanism, subgrade moisture migration character and rules as well as influence factor,including moisture migration law caused by capillary action, rainfall and crack seepage, water level fluctuation. Such as the changes of water distribution and pore-water pressure which trigger disease of the road strength and stability, structural safety .Combined with the properties of red clay with high liquid limit and expansion in the South area, we carry out laboratory test research on water vapor transport in unsaturated soil, including the capillary water rise test, routine shear consolidation test, permeability test and soil water characteristic curve measurement.Finally, set a finite element model and do moisture migration simulation research on unsaturated soil subgrade with Geo-studio software, that are changes in water distribution and the limit height of capillary water can reach, water content and pressure changes under different rainfall conditions. And also analyze the law of moisture migration in subgrade under the conditions of different rainfall time and boundary conditions, whether there are cracks or not on embankment surface. Base on the moisture transportation modeling results of unsaturated-soil , lead to the necessity of pavement drainage treatment measures.