Abstract: In order to investigate the influence of multi-factor coupling effects on frozen Lanzhou loess dynamic parameters, Lanzhou loess distributed in seasonal frozen soil region of western China was investigated experimentally. The dynamic parameters of frozen Lanzhou loess under different conditions were examined by dynamic triaxial test, including confining pressure (0.1, 0.2, 0.3 MPa), soil temperature (−1, −3, −5 ℃), soil water content (14%, 16%, 18%) and vibration frequency (1, 2, 4 Hz). Based on the test results, the changing rules of the maximum dynamic elastic modulus, equivalent viscous damping coefficient and reference strain amplitude of frozen Lanzhou loess under the coupling influence factors of temperature, confining pressure, water content and loading frequency were analyzed. Test results show that the coupling factors including temperature, water content, loading frequency and confining pressure have different influences on the dynamic elastic modulus, reference strain amplitude and equivalent viscous damping coefficient of frozen Lanzhou loess. It can be found that the dynamic elastic modulus and reference strain amplitude of frozen Lanzhou loess are influenced most significantly by soil temperature, and the equivalent viscous damping coefficient is the most sensitive to the loading frequency. Moreover, based on the experimental results, the four factors affecting the frozen Lanzhou loess are normalized and dimensionlessized, and the prediction formulas of the dynamic parameters of the frozen Lanzhou loess are proposed using multiple regression analysis method. This will be beneficial to quickly predict the changing characteristics of the dynamic parameters of the frozen Lanzhou loess under the influence of the coupling effect of multiple factors. The formulas are helpful for rapid prediction of dynamic parameters of frozen Lanzhou loess under the multi-factor coupling influence effects.

Key words: frozen Lanzhou loess, step loading, dynamic elastic modulus, equivalent viscous damping coefficient, reference strain amplitude, coupling effect