TESTING STUDY ON DYNAMIC PROPERTIES OF EXPANSIVE SOIL AND IMPROVED EXPANSIVE SOIL
膨胀土与改性膨胀土的动力特性试验研究

Based on the improving tests of expansive soil roadbed of Chengdu Bypass Expressway,permanent deformation and dynamic properties of expansive soil and improved expansive soil under repeated loading are studied using dynamic triaxial test. Under the different confining pressures,the relationships among elastic strain, cumulative plastic strain,dynamic strain and the number of loading repetition are analyzed respectively. The three stages of cumulative plastic strain of expansive soil are easier to distinguish from log-log coordinate system than from common coordinate system. The log-log relationship between the cumulative plastic strain and the number of loading repetition is approximately linear when ignore the primary stage and the tertiary stage of material deformation. There is similar relationship between dynamic strain of expansive soil and the number of loading repetition. The dynamic properties,such as dynamic elastic modulus,dynamic cohesion,dynamic friction angle, damping ratio,of expansive soil and improved expansive soil are compared. The results show that the engineering characteristics and strength parameters of improved expansive soil are significantly improved.