Expansive Soil Filling Improvement Test of Railway Subgrade

Using expansive soil as the filling of railway subgrade is a cause of its excessive deformation of the upper part of the railway track which endangers the safe operation of the railway.It cannot be directly used as subgrade filling,but must be improved.In this paper,combining with pilot projects of Wuhan-Ankang 2nd railway subgrade,through field sampling,the indoor experimental research about expansive soil improved by lime is carried on,as well as the comparative analysis of expansive soil′s physical and mechanical properties before and after improvement and the improvement effects.The results show that: it is feasible to use lime as a modifier of expansive soil;the expansive soil modified by lime has significantly lower plasticity,higher strength,poorer swell-shrink characteristics,and its water-logged stability is advanced,which can meet the requirement of railway subgrade filling with speed of 200km/h.