Abstract:The mechanical properties of red clay under impact loading are studied by triaxial dynamic test system. The test schemes include various impact loadings,various confining pressures and various numbers of impacts. The deformation and shear strength of red clay samples after impact loading are analyzed. The studies show that the stress-strain curves of clay samples subjected to impact loading are higher than those before subjected to the numbers of impacts,which show the increase of shear strength. With the increase of confining pressure,the increased values of shear strength are more obvious by increasing the numbers of impacts;namely,the reinforcement effect of red clay foundation by dynamic compaction is more obvious for deep soil layers. With the increase of impact loading in the range of testing confining pressure,the shear strength of the red clay correspondingly increases.