A model for excess pore water pressure increment in saturated coral sand considering loading frequency

In order to predict the generation characteristics of the excess pore water pressure(u_e) in saturated coral sand under different cyclic loading frequencies( f ), a series of consolidated undrained cyclic triaxial tests are conducted on saturated coral sand by using the GDS dynamic triaxial apparatus. The effect of loading frequency( f ) on the excess pore water pressure(u_e) is then analyzed in conjunction with the concepts of pore pressure increment ratio(β_{Δμ, N})and effective dynamic shear stress ratio(α_{dE, N}). These laboratory cyclic tests show that the patterns of u_e generation in those test specimens are related to the paths of loading frequency ( f ), particle gradation and (CSR). β_{Δμ, N} can be divided into a stable stage and a rising stage with the development of the number of cycles(N), and the loading frequencies( f ), the mean particle size(d₅₀), and the cyclic stress ratio(CSR) have a significant effect on the β_{Δμ, N} of the plateau. Then, the comparison expression about the corresponding law of influences, while these factors have little effect on the logarithmic decay rate of the effective stress(ξ_{μ, N-1}). Considering the above factors, this paper constructs an excess pore pressure increment model for saturated coral sands considering the effect of cyclic loading frequency. The model is validated by selecting experimental data from existing research results, which shows that the model has a good predictive capability.