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

摘要

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 epsilon(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 fN 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. (C) 2015 Elsevier Ltd. All rights reserved.