Abstract: A series of laboratory tests were conducted on the improvement of red clay with lime at different lime contents to obtain the variation rules of physical properties,mechanical properties,and water stability.Combined with the action mechanism of lime to improved red clay,the engineering characteristics of the improved red clay with lime were analyzed.The results showed that lime can significantly improve the physical properties,mechanical properties,and water stability of the red clay.It is recommended that the reasonable lime content should be 3%.The lime content of 3% is a mutation point of the shear strength of red clay.When the lime content is less than 3%,the lime content has a strong effect on the mechanical properties of red clay.When the lime content is more than 3%,even if a large amount of lime is added,the physical and mechanical properties of the red clay cannot be significantly enhanced.Finally,the SEM experiment is used to study the strength growth mechanism of the improved red clay.

Key words: red clay, lime content, physical and mechanical properties, microstructure