Bearing Strength and Swelling Behavior of Jingmen Expansive Soil

The influence of swelling potential grade, water content and dry density on California Bearing Ratio (CBR) of expansive soils from Jingmen, China was studied and empirical formulas describing the relationship of CBR value, dry density and the compaction degree of soil were derived. It is found that the CBR values depend on the water content, the dry density and the structural state after soaking expansion, and its variations with the water content, compaction effort and swelling potential grade are similar to the compaction curves. The water content of the maximum CBR is usually higher than the optimum water content and this difference decreases as the compaction effort decreases. It is concluded that the water content for expansive soil for subgrade construction control should be slightly higher than the optimum water content and lower than the plasticity limit, while the dry density should be slightly lower than the maximum dry density.