ANALYSIS OF DYNAMIC STRESS-STRAIN RELATIONSHIP OF LOESS

This paper aims to study dynamic properties of loess. This study is helpful to the subject on how to avoid or decrease the seismic disasters on loess ground. Dynamic triaxial tests are carried out with saturated remoulded soil samples taken form loess sites in Xi'an, China. Dynamic stress and strain relationship as well as the rule of the accumulated residual strain are obtained from the test results. Linear relationship between accumulated residual strain and vibration circle under constant amplitude circular loading is presented. A hypothesis about the accumulated residual strain is proposed. 1D dynamic constitutive relationship model which can well describe the real relationship between dynamic stress and strain under irregular dynamic loading is established. Numerical program with this model is developed and an example is tested. Numerical results of hysteresis loop, accumulated residual strain, amplitude of dynamic stress and damping ratio show good agreement with test results. It is indicated that the hypothesis of accumulated residual strain and the 1D dynamic constitutive relationship model can accurately simulate the dynamic triaxial tests of saturated remoulded loess.