Experimental Study on Swelling Property of Subgrade Soil in a First-Class Highway

Based on the experimental study on water contents,liquid limit,plastic limit,particle composition,mineral content,free expansive ratio and swell-shrink total ratio of the filled soil in a first-class highway,this paper evaluates the property of the subgrade soil by using the plasticity chart and considering various indices.It is concluded that the filled soil is silt soil with high liquid limit and plastic limit,which has the low swelling property in natural state.According to the results of the compaction test and bearing ration test,it is discovered that the filled soil also has the swelling property after being compressed,which may result in the crack of the subgrade with the change of the water contents.