Numerical Analysis and Experimental Study of the Mechanical Response of Pavement Slab Supported on an Inhomogeneous Settlement

The inhomogeneous settlement of subgrade seriously affects the safety of aircraft operation. To investigate the mechanical response of pavement slabs supported on an inhomogeneous settlement, a three-dimensional model of aircraft load–pavement structure–heterogeneous pavement was established; then, the inhomogeneous settlement conditions were simulated by setting a different reaction modulus between adjacent subgrades. Finally, both numerical simulation and experimental study methods were used to analyze the flexural tensile stress and vertical displacement of the pavement slab in inhomogeneous settlement conditions under the loading effects of typical aircrafts (A320 and B737-800). The results indicate that the strain of pavement slabs increases as the change rate of an inhomogeneous subgrade support increases. Increasing the thickness of the pavement slab and reducing the inhomogeneous subgrade support can effectively improve the mechanical performance of the pavement structure. For B737-800, with the change rate of the inhomogeneous subgrade support increasing from 0% to 85.71%, the amplitude of the flexural tensile stress of the pavement slab increased by 34%. The pavement slab with a thickness of 0.36 m experienced flexural–tensile failure. For pavement slabs with thicknesses of 0.38 m and 0.40 m, the maximum inhomogeneity of the subgrade roof support should not exceed 33% or 62%, respectively. Therefore, the effect of the horizontal inhomogeneous subgrade support caused by long-term environmental action should be considered when designing pavement slabs.