LEAP-UCD-2017 Centrifuge Tests at Cambridge

Abstract

As part of the LEAP project the seismic response of a liquefiable 5 slope was modelled at a number of centrifuges around the world. In this paper the two experiments conducted at Cambridge University are discussed. The model preparation is detailed with particular emphasis on the sand pouring, saturation and slope cutting process. The presence of the third harmonic in the input motion is shown and its significance discussed. The potential for wavelet denoising to filter random electrical noise from the pore pressure traces is illustrated. CPT strength profiles are highlighted and a possible softer layer in one of the tests is discussed. Whilst the specifications called for one dense and one loose test, the likelihood that both Cambridge tests were loosely poured is assessed. The PIV technique is used to obtain the displacements of the slope during the test. Finally, the correspondence between the PIV displacements and physical measurements of the marker movements is compared.

Introductory consideration supporting the idea of the release of elastic waves in hysteretic soil

“…[Durante, 2015]) and in centrifuge (e.g. [Madabhushi et al, 2020]) is sometimes observed in terms of the recorded input motions at base. In particular, high harmonics are apparently more prominent at base in centrifuge tests, notwithstanding the intended input motion should consist only of a single harmonic.…”