Key Parameters for the Finn Liquefaction Constitutive Model of Saturated Sand

Taking the medium-fine sand layer along Minjiang River as prototype, small-scale shaking table tests based on 3 factors and 3 levels orthogonal design were conducted to discuss the liquefaction characteristic qualitatively. Meanwhile, the dynamic numerical simulations for the typical excitation time-history were carried out upon the FLAC3D numerical platform by using Finn liquefaction constitutive model. The simulation results showed that the Finn constitutive model could well reflect the increase of pore pressure, the decrease of effective stress and the liquefaction characteristic of saturated sand under seismic excitation. On the other hand, the key parameters C₁ and C₂ in the Finn liquefaction constitutive model might influence the simulation results significantly. A large number of numerical simulations with different key parameters were carried out sequentially. The peak value and the stable value in the time-history of excess pore pressure ratio were focused and compared with experimental results. Therefore, the key parameters C₁ and C₂ for the Finn liquefaction constitutive model of Minjiang saturated sand were calibrated and suggested as 1.30 and 0.31, respectively. Meanwhile, the saturated sand also tended to dilate slightly during excitation time-history, which appeared synchronously with liquefaction.