Experimental set-up in the centrifuge study of a laterally loaded energy pile

This paper examines the displacements of energy piles laterally loaded in dry sand using the centrifuge of the Geotechnical Centrifuge Laboratory at Gustave Eiffel University. Both grout and aluminium energy pile models are introduced, then tested by a four-point bending test to evaluate their flexural characteristics. Resulting from mechanical tests, the aluminium energy pile is selected for further study. A 20D long aluminium pile (where D is the diameter of the pile) is studied at 26.7g using physical modelling, representing a 16 m long pile at prototype scale. The pile model is subjected to a horizontal load of 430 kN followed by six heating-cooling cycles resulting in an approximate 2% increase in lateral displacement under ΔT≈1°C. Temperatures are monitored inside the pile and at its outside surface using thermocouples, while mechanical behaviour is observed using displacement sensors and optical fibre Bragg grating (FBGs) sensors. Accumulation of horizontal displacement is observed. The FBG data also enable analysis of pile lateral displacement, bending moment and soil reactions.