Study on the effects of drying–wetting cycles on the dynamic elasticity modulus of weathered red sandstone soil

In this paper, the effect of drying–wetting cycles on the dynamic elasticity modulus of weathered red sandstone soil was studied based on a series of unconsolidated undrained dynamic triaxial tests under different confining pressures and with the help of the Hardin–Drnevich model. The main results from this work as follows: (1) Hardin–Drnevich model can well express the hyperbolic behaviors of dynamic backbone curves of the weathered red sandstone soil exposed to drying–wetting cycles. (2) Both the maximum dynamic elasticity modulus and the dynamic elastic modulus of the weathered red sandstone soil decreased linearly with numbers of drying–wetting cycles under a certain confining pressure. The dynamic elasticity modulus decreased non-linearly with the increase of dynamic strain. (3) The maximum dynamic elastic modulus of the weathered red sandstone soil decreased by 19.62% to 70.91%, 21.16% to 71.07%, and 29.53% to 77.36%, respectively after 3 to 12 drying–wetting cycles under confining pressures of 100, 200, and 300 kPa. The rate at which the maximum dynamic elastic modulus decreases is basically the same under different confining pressures.