High-cycle fatigue interaction between soil foundation and concrete slab under moving wheel-type loads

Abstract

Small-scale fatigue experiments were conducted to investigate failure modes of the coupled system of soil foundation and concrete slab subjected to wheel-type moving loads. Based on these experiments, the numerical fatigue simulation was validated by integrating constitutive models of cracked concrete and soil foundations. The finite element code used in this study is built by combining the multi-directional fixed crack model of concrete with the multi-yield surface plasticity for nonlinear shear and volumetric fatigue of soil. The computed deflections and failure modes of the pavement system show close correlation with experiments. To clarify the real working conditions, full-scale modeling was investigated as well. The results depict that the necessary and sufficient slab thickness varies nonlinearly according to the soil rigidity, and that the medium compacted soil foundation requires the thicker slabs rather than the current design value rooted in a beam theory on elastic foundation. Thus, a key factor to revise the design scheme is proposed in terms of the balanced slab thickness associated with the nonlinearity of soil foundation.