Taking red sandstone as the research object

the intact and flawed red sandstone specimens coated with liner were made using a cement-based thin spray-on liner. The study examined how the thin spray-on liner affected the strength

deformation

and energy evolution of intact and flawed red sandstone under uniaxial compression. Furthermore

the study analyzed how the thin spray-on liner influenced the crack propagation characteristics of sandstone with different inclination angles through particle flow PFC3D software. The results indicate that red sandstone coated with the thin spray-on liner exhibited higher peak strength and strain compared to uncoated specimens. Moreover

the improvement coefficient for flawed sandstone exceeded that of intact specimens. In the post-peak stage

the internal rock of specimens with the thin spray-on liner was damaged

resulting in the formation of tensile cracks on the liner’s surface

although the specimens did not fully collapse. The total energy

elastic energy

and dissipation energy of specimens with a thin spray-on liner are greater than those of uncoated specimens. Moreover

a greater amount of input total energy is converted into dissipation energy post-coating. The PFC3D simulation results indicate that applying a thin spray-on liner can increase the initiation stress and peak strength of crack specimens at different inclination angles. The influence of a thin spray-on liner on the failure modes of specimens with varying crack angles. Specifically

at a 15º inclination angle

the thin spray-on liner hinders the propagation of tensile cracks in the post-peak stage. Conversely

at a 75º inclination angle

the crack propagation behavior of specimens

whether coated or uncoated with a thin spray-on liner

is similar. These research findings can provide a reference for the application thin spray-on liners in engineering applications.