Study on additional stress diffusion characteristics of waste tire artificial foundation

The study of additional stress diffusion law in the artificial foundation has a significant importance for analysing the overall deformation mechanism of the 'foundation + underlying soil' coupled system. Through plate loading tests, the soil pressure within the foundation under various conditions was measured, and the corresponding P-S curves were obtained. By analysing the trend of P-S curves and evolution of the compressive stiffness, the failure mechanism of the Artificial Foundation and single column composite body was explained. The calculation methods for the interface rubber content ratio and modified volumetric rubber content ratio, which quantify the contact relationship between tires and soil and the interlocking relationship between tires, were provided. Through thin plate spline interpolation, an additional stress field was established, which demonstrate the impact of the rubber content on the diffusion shape of the additional stress. The results indicate that sliding of the underlying layer is the primarily failure mode of the double-layer foundation system. The necessary condition for the hoop effect vanishing is the adequacy of lower boundary stiffness. Compared to plain soil, the bearing capacities of the artificial foundations increase by 2.33–5.72 times. Laying geo-textile and geo-grid between layers can effectively enhance the initial compression stiffness and prolong the linear bearing phase. With an increase in rubber content, the additional stress diffusion angle increase by as much as 16.2% to 79.9%. Finally, a stress diffusion function was established by fitting the measured soil pressure values.