Abstract: In order to comprehensively utilize solid waste coal gangue, coal gangue concrete piles were prepared by replacing part of traditional fine aggregate. Laboratory model tests of coal gangue pile-net composite embankments under reinforced cushions of geocells and geogrids were conducted to analyze the differences in load-settlement relationships of the embankment top surface, load transfer capabilities of the reinforced cushions, and stress distributions within the piles. Additionally, a finite element calculation model was established to investigate the stress and deformation patterns of different reinforcing materials, revealing the mechanism of geocells applied in reinforced cushions. The results indicate that, in this test, compared to geogrids, the geocell reinforced cushion significantly reduced the settlement of the embankment top by approximately 29.71%. Under the geocell reinforced cushion, the attenuation of soil pressure at the top of the piles and between piles was approximately 61.51% and 56.35%, respectively, fully utilizing the raft effect and stress diffusion effect. When using a geocell reinforced bedding, the embankment load was more effectively transferred to the coal gangue piles, with the extreme values of pile stress at the center of the roadbed and along the cross-section of the roadbed being 1.78 and 1.80 times greater, respectively, than those using geogrid reinforced bedding. The stress distributions of geocells and geogrids exhibited "V"-shaped and "U"-shaped patterns, respectively, and the maximum stress value of geocells was greater than that of geogrids. The unique honeycomb structure of the geocell exerts lateral hoop and rib friction resistance on the embankment fill, effectively diffusing the embankment load through its own tension and deformation.

Key words: pile-net composite embankment, coal gangue pile, geocell, load transfer of reinforced cushion, pile stress