LEAP-UCD-2017 Comparison of Centrifuge Test Results

Abstract

This paper compares experimental results from every facility for LEAP-UCD-2017. The specified experiment consisted of a submerged medium-dense clean sand with a 5-degree slope subjected to 1 Hz ramped sine wave base motion in a rigid container. The ground motions and soil density were intentionally varied from experiment to experiment in hopes of defining the slope of the relational trend between response (e.g., displacement, pore pressure), intensity of shaking, and density or relative density. This paper is also intended to serve as a useful starting point for overview of the experimental results and to help others find specific experiments if they want to select a subset for further analysis. The results of the experiments show significant differences between each other, but the responses show a significant correlation, R 2~0 .7-0.8, to the known variation of the input parameters.

Comparison of LEAP-UCD-2017 CPT Results

“…Inverse equations from the linear regression lines were used then to determine dry density from penetration resistance. Kutter et al (2019b) showed the densities calculated from penetration resistance at 2.0 m depth were better correlated to liquefaction performance measures than densities from mass and volume.…”

“…When that point is corrected back to the trendline, the density decreases to 1602 kg/m 3 . Kutter et al (2019b) showed that at 2.0 m depth, densities determined from penetration resistances better correlate with liquefaction performance measurements than densities from mass and volume measurements. Tabulated in Table 6.2 are the reported dry densities from mass and volume and densities calculated from the linear regression and penetration resistance.…”

“…6.7 may be explained by container width and model size. Kutter et al (2019b) showed however that the resistance to liquefaction is better characterized by the cone penetration resistance than it is by the measured mass and volume. It is possible that the effects of model size on penetration resistance somehow compensate the effects of model size on liquefaction resistance (i.e., perhaps q c increases as container size decreases, and liquefaction resistance increases as container size increases.…”

Difference and Sensitivity Analyses of the LEAP-2017 Experiments

“…The sand was deposited through pluviation in a level rigid container to achieve a range of mass densities (with a reference mean value of 1652 kg/m 3 ). The corresponding relative densities varied from about 50 to 85% (evaluated using the minimal and maximal densities reported by Kutter et al (2018Kutter et al ( , 2019, as displayed in Fig. 7.2).…”

“…ij and ΔA 2þHz ij are the two main input motion parameters that varied during the analyzed 26 LEAP centrifuge tests. The tested soil models also had variability in soil deposition and achieved grain packing (as documented by the mass densities reported by the different centrifuge facilities (Kutter et al 2018(Kutter et al , 2019). These variations have a direct effect, for instance, on stiffness properties which in turn affect the deposit response.…”