In a recent technical note we explore the convenience of including the loading frequency factor in the HCA clay model based on the interpretation of a series of cyclic undrained triaxial tests performed on three different clay materials.

Experimental observations reported in the literature, based on cyclic triaxial and cyclic simple shear tests, show that the loading frequency influences the excess pore pressure and strain accumulation for fine-grained soils under undrained conditions. This technical note explores the convenience of including the loading frequency factor in the high-cycle accumulation clay model based on the interpretation of a series of cyclic triaxial tests considering three different clay materials, namely Dorfner kaolin, Lower Rhine clay and Onsøy clay. As a result, the normalization of the pore pressure accumulation rate with the amplitude function f_{ampl} purifies the data from the influence of loading frequency and thus no explicit frequency function f_f is required.

Tafili, M., Albared, A., Prada Sarmiento, L. F. & Wichtmann, T. (2023). Loading rate influence on high-cyclic loading of clays. Soil Dynamics and Earthquake Engineering. DOI: https://doi.org/10.1016/j.soildyn.2023.108103

The paper is available at the following Link