Fractional-order derivative Kelvin model of cumulative pore pressure under cyclic loading

The settlement caused by traffic loading on soft ground has serious effects on subways, tunnels and highway bridges. Therefore, it is important to study the long-term settlement caused by traffic loading. A series of undrained cyclic triaxial tests was conducted on saturated soft clay that involved different initial effective confining pressures, dynamic stress ratios and consolidation modes. The relationship between cumulative pore pressure and cyclic times was obtained. The general Kelvin model and the fractional-order derivative Kelvin model were used to simulate this relationship. Simultaneously, the genetic algorithm was used to optimize the parameters of these two models. When comparing the calculation and test values, it is verified that the general Kelvin model can simulate the cumulative pore pressure only when the dynamic stress ratio is small, and the fractional-order derivative Kelvin model is more suitable for simulating the cumulative pore pressure under cyclic loading.