Interfacial shear behaviors of geocell-granular solidified sediment considering the particle breakage and geocell sizes

The practicability of granular solidified sediment (GSS) as a geocell-reinforced structural fill material behind retaining walls and reinforced soil slopes under pull-out conditions is investigated through the large-scale direct shear test. The effect of geocell sizes on the interaction characteristics between geocell and GSS under different normal stresses (40, 60, 80 and 100 kPa) is studied, and particular interest is focused on the impact of particle breakage on interfacial shear properties. The test results show that the peak shear strengths of reinforced GSS specimens are greater than those of natural sand (SP) and crushed stone (G7) samples in both reinforced and unreinforced cases, and reinforced GSS specimens have all the reinforcement strength coefficients more than one, indicating that GSS particles have the stronger ability to resist grains sliding along the shear plane. Significant particle breakage phenomenon of GSS particles is observed during the shearing process, and the interaction between geocell and GSS aggravates the particle crushing, weakening geocell's performance. Specifically, the shorter the spacings between welded junctions of geocell, the higher the relative particle breakage ratios and fractal dimensions, and the greater effect on geocell's reinforcement strength coefficients and interface cohesions, but geocell's height relatively weak influence GSS particle breakage. In general, it has been recommended to utilize GSS as a geocell-reinforce structural fill material in environments under lower normal stress (sigma n <= 100 kPa) and larger geocell's pocket size.