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The study of dynamic brittleness and failure characteristics is of guiding significance for promoting the full exploitation and utilization of deep sandstone reservoirs. At present, there have been more comprehensive studies on the mechanical properties of deep sandstone reservoirs, but the study of mineral composition on the dynamic brittleness and failure characteristics of deep sandstone reservoirs is relatively weak. In this paper, XRD mineral composition analysis, uniaxial compression experiment, and Brazilian splitting are used to study the influence of mineral composition on mechanical properties and failure characteristics of deep sandstone reservoirs. It was concluded that (1) the mineral compositions of deep sandstone reservoirs are mainly three kinds of oxides: SiO2, Al2O3, and CaO. The failure modes of deep sandstone reservoir samples under uniaxial compression are more complicated, with tension failure and shear failure each accounting for half. In the Brazilian split test, the failure modes of sandstone samples are mainly shear failure. (2) The compressive strength decreases obviously with the increase of CaO content. The contents of SiO2, Al2O3, and CaO all have a great influence on the residual strength of deep sandstone reservoirs. The deformation modulus decreases gradually with the increase of Al2O3 content. (3) The brittleness increases slightly when the content of SiO2 increases, while the brittleness decreases slightly when the content of Al2O3 increases. Considering factors such as strength, modulus, brittleness, and failure characteristics, SiO2 content has the greatest influence on the mechanical properties of deep sandstone reservoirs, followed by Al2O3 content, and CaO content has the least influence. The research results have a guiding role in the utilization and development of oil and gas resources in deep sandstone reservoirs and promote oil and gas development from the middle to deeper layers. [ABSTRACT FROM AUTHOR]

• 74 specimens with seven bedding angles and five confining pressures were tested. • The lowest strength occurs at bedding angle of 45°–60° and greatest below 15°. • The fracture angle of slate presents a U-shaped curve. • The lowest modulus occurs at bedding angle of 45°–60°, and greatest at 75°–90°. • Even if confining pressure is small, the modulus is significantly increased. The physical properties of slate in buildings are affected by its bedding angle and confining pressure. A total of 74 slate specimens with seven bedding angles and five levels of confining pressure were tested in uniaxial and triaxial compression tests. The effects of bedding angle and confining pressure on the mechanical behaviour of the brittle slate were quantified. The test results showed that, with the increase of confining pressure, the compressive strength of rock increased significantly. The variation in compressive strength of slate under confining pressure could be described by the parabolic Mohr-Coulomb strength criterion. The strength of slate is the lowest when the bedding angle is 45°–60°, and greatest when it is below 15°. When unconfined, the fracture angle of slate is 65°–90°. With increased confining pressure, the fracture angle of slate tends to 45° from above. As the bedding angle increases from 0° to 90°, the fracture angle of slate presents a U-shaped curve. When the bedding angle is 75°–90°, the deformation modulus of slate is greatest, and is minimised when the bedding angle is 45°–60°. Even if the confining pressure is low, the deformation modulus of slate is significantly increased compared to that in unconfined conditions. It proves that shotcrete treatment of the rock surrounding a tunnel will greatly improve the supporting effect thereon. [ABSTRACT FROM AUTHOR]