Mechanical properties and crack propagation behavior of flawed red sandstone coated with a thin spray-on liner under uniaxial compression
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 15° inclination angle,the thin spray-on liner hinders the propagation of tensile cracks in the post-peak stage.Conversely,at a 75° 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.