Full-scale performances of the slab track subgrade filled with basalt fiber-reinforced foamed concrete

Foamed concrete has been used to address the issue of differential settlement in high-speed railway subgrades in China. However, to enhance crack resistance, reinforcement is still necessary, and further research is required to better understand the performance of foamed concrete in subgrade applications. To this end, a series of tests—including uniaxial compressive and dynamic triaxial tests—were conducted to comprehensively examine the effects of basalt fiber reinforcement on the mechanical properties of foamed concrete with densities of 700 and 1000 kg/m³. Additionally, a full-scale model of the foamed concrete subgrade was established, and simulated loading was applied. The diffusion patterns of dynamic stress and dynamic acceleration within the subgrade were explored, leading to the development of experimental formulas to calculate the attenuation coefficients of these two parameters along the depth and width of the subgrade. Furthermore, the dynamic displacement and cumulative settlement were analyzed to evaluate the stability of the subgrade. These findings provide valuable insights for the design and construction of foamed concrete subgrades in high-speed rail systems. The outcomes are currently under consideration for inclusion in the code of practice for high-speed rail restoration.