Reliability analysis of parallel tests on DCIEM-40 Higee shaker

The parallel testing of the High Gravity Technology Shaker (Higee shaker) is a crucial method for evaluating the effectiveness of geotechnical seismic calculation and analysis techniques, as well as for advancing test technology. This study addresses the widespread controversy regarding the reliability of test technology due to the discrepancies observed in international parallel test results. It elaborates on the key technologies of the DCIEM-40 Higee shaker, including load control, model preparation, data measurement, and other testing procedures. By modifying two sets of parallel tests under a single variable, this research explores the consistency and comparability of results obtained under different conditions, thereby verifying the feasibility of conducting parallel tests and the reliability of the associated key technologies. The findings indicate that: (1) The constant-amplitude sine sweep motion exhibits continuous frequency and uniform amplitude characteristics compared to white noise waves, making it more effective for identifying the quality and self-oscillation cycles of the test model. The compression seismic waves generated with varying centrifugal accelerations and amplitudes yield nearly identical prototype waveforms, with an average peak deviation of at most 2.99% and a maximum error in the spectral area of 9.86%. (2) The values of the excess pore water pressure ratio at different horizontal positions at the same depth, as well as the excellence cycle of the site, are generally consistent with the theoretical values within the same model. The measured periods closely align with the theoretical values, and the dynamic responses of the excess pore water pressure ratio and acceleration at different depths exhibit strong correlation in both amplitude and phase, confirming the accuracy of model preparation and static dynamic measurements. (3) In parallel tests, the acceleration, excess pore water pressure ratio, displacement, and recordings at the same locations across different models show considerable agreement, further substantiating the stability and repeatability of the model preparation and experimental measurement techniques. Additionally, the multi-physical seismic responses of various soils and structures under the influence of a single variable demonstrate significant differences, thereby validating the comparability and feasibility of the parallel tests. The results of this research provide valuable insights for the operation of existing Higee shakers, the development of new equipment, and the standardization and normalization of test technology in China.