Experimental study of expansion characteristics of compacted expansive soil

In order to study the characteristics of expansive soil,load-free swelling rate and loaded swelling rate tests are carried out on the compacted expansive soil samples from Middle Route of South-to-North Water Transfer Project in Nanyang with different initial moisture contents and compactnesses.The relationship between initial moisture content,compactness,load and swelling characteristics of the Nanyang compacted expansive soil,are studied emphatically.Test results indicate that:when the initial moisture content is same,load-free swelling rate of the expansive soil takes on a good linear growth relationship between the compactness with the compactness increased;when the compactness is same,load-free swelling rate of the expansive soil increases with the initial moisture content decrease;when water content is greater than the optimum water content can significantly inhibit the swelling of expansive soil;smaller loads can suppress most of the expansion of the expansive soil;through the cross-analysis method,we can see,when the load is small,the impact of water content to loaded swelling rate is greater than the impact of compactness;when the load continues to grow,the impact of compactness to loaded swelling rate is greater than the impact of water content.