Preliminary results of instrumented laboratory flow slides

The liquefaction tank is an experimental facility developed to conduct physical scale model tests of liquefaction flow slides. We developed the liquefaction tank to evaluate the performance of advanced numerical models for submerged slopes composed of sand. For the long-term, the research with the liquefaction tank aims at composing a database with high-quality experimental results of liquefaction flow slides, in which properties related to the soil, degree of saturation, geometry, triggering and mitigating measures will be varied.
This paper addresses the first results obtained with the liquefaction tank. We used a fluidization system to create a uniform, loosely packed sand bed. The liquefaction tank was subsequently tilted uniformly, while measuring the pore pressures at the base of the sand bed. Furthermore, the stability of the slope was monitored using a camera system pointed at the transparent side of the tank. We conducted around 30 tilting tests on a level sand bed while varying consolidation time, density and tilting rate.
We were able to reproduce liquefaction flow slides below a particular threshold density. The moment of failure was noted by an instant, uniform liquefaction of the sand bed, preceded by an abrupt increase of excess pore pressures. The results in terms of failure angle and measured pore pressures were consistent and reproducible. The measured failure angle was much lower than anticipated from results of element tests in literature. Future research aims at relating the results to the response during undrained triaxial tests and the effect of mitigating measures.