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

In order to predict the generation characteristics of the excess pore water pressure(ue) in saturated coral sand under different cyclic loading frequencies(f), a series of consolidated undrained cyclic triaxial tests was conducted on saturated coral sand by using the GDS dynamic triaxial apparatus. The effect of loading frequency(f) on the excess pore water pressure(ue) was then analyzed in conjunction with the concepts of pore pressure increment ratio(βΔμ,N)and effective dynamic shear stress ratio(αdE,N). These laboratory cyclic tests showed that the patterns of ue generation in those test specimens are related to the paths of loading frequency(f), particle gradation and (CSR). βΔμ,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 βΔμ,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(ξμ,N-1). Considering the above factors, this paper creates a excess pore pressure increment model for saturated coral sands considering the effect of cyclic loading frequency. The model was validated by selecting experimental data from existing research results, which showed that the model has a good prediction ability.