Inspection of a high-cycle accumulation model for large numbers of cycles (N=2 million).

The high-cycle accumulation (HCA) model for sand proposed by Niemunis et al. (2005) [16] has been developed based on numerous drained cyclic triaxial tests with 100,000 cycles. In the present paper the validity of the HCA model, in particular its function f N and flow rule m , for larger numbers of cycles is inspected. For that purpose, drained long-term cyclic triaxial tests with 2 million cycles have been performed on 13 clean quartz sands with different grain size distribution curves. For all tested sands, the function f N , describing the shape of the strain accumulation curves ε acc ( N ) , has been found suitable up to 2 million cycles. The same applies to the cyclic flow rule m , determining the ratio of the volumetric and deviatoric strain accumulation rates. Based on the data from the long-term tests, correlations between the HCA material parameters entering f N and characteristics of the grain size distribution curve ( d 50 and C u ) have been improved for the application to 2 million cycles. These correlations are suitable for a simplified calibration of the HCA model and were validated up to 100,000 cycles only so far. [ABSTRACT FROM AUTHOR]