Anisotropic mechanical characteristics of carbonaceous slate under conventional compression
To investigate the influence of bedding angle on the mechanical properties of carbonaceous slate,uniaxial and triaxial compression tests were conducted on carbonaceous slate samples with varying bedding angles.The objective was to study the effects of bedding angle on the strength,deformation parameters,and failure modes of the carbonaceous slate.Additionally,a cohesive zone model was established using ABAQUS finite element software for numerical simulation analysis.The research findings indicate that during compression,the stress-strain evolution of carbonaceous slate with different bedding angles exhibits three stages:compaction,quasi-elastic deformation,and failure with stress drop.Under triaxial compression,the stress-strain curves of carbonaceous slate rarely display compaction characteristics,and as confining pressure increases,the failure mode gradually transitions to ductile failure.In uniaxial compression,when the bedding angle is 0°,the carbonaceous slate exhibits shear failure across the bedding plane.At bedding angles of 30° and 45°,it shows weak plane shear failure along the bedding plane.When the bedding angle is 90°,tensile-shear failure occurs.The failure modes of carbonaceous slate with different bedding angles are strongly controlled by the bedding angle and less influenced by confining pressure.The strength and deformation parameters of carbonaceous slate with various bedding angles exhibit anisotropic characteristics,albeit to different degrees.The anisotropy ratios of peak strength for carbonaceous slate under different confining pressures are all above 1.5,while the anisotropy ratios of elastic modulus range from 1.2 to 1.35.The shear strength parameters of carbonaceous slate,derived from the relationship between strength and confining pressure,reveal significant anisotropy in cohesion.The research findings provide a theoretical foundation for the prevention and control of instability in surrounding rock of deeply buried carbonaceous slate tunnels.6 tabs,14 figs,21 refs.
tunnel engineeringcarbonaceous slateuniaxial and triaxial testanisotropybedding inclination anglenumerical simulation
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