Small-scale modelling of reinforced concrete for physical model tests, and its application in centrifuge testing of a soil-structure interaction problem

This paper will discuss the improvement of seismically unstable slopes using a row of discretely spaced vertical piles, to indicate some of the key issues involved in the physical modelling of soil-structure interaction problems at small-scale, in this case, within a geotechnical centrifuge. A 1V:2H sandy slope is modelled at a scale of 1:50 using the beam centrifuge and earthquake simulator at the University of Dundee and improved using piles which nominally represent the same prototype reinforced-concrete (RC) pile, but modelled in different ways. ‘Elastic’ model piles act as a benchmark against which damageable piles made of a novel model micro reinforced-concrete are assessed. This model concrete is able to simultaneously model both the bending stiffness (EI) and strength of realistic full-scale concrete piles. Two different sections will be considered, representing (i) a ‘well-detailed’ section which is designed not to form a plastic hinge during slope movement (i.e. the soil yields around the piles before they become damaged); and (ii) a ‘weak’ section with a similar EI but much lower moment capacity (i.e. so that the pile fails before the soil yields). In this way, it will be shown how useful the model concrete is in assessing the performance of soil-structure systems containing reinforced concrete through the use of centrifuge model tests, or other small scale model tests that involve geometric scaling.