Abstract In order to derive the influence patterns of confining pressure, fracture dip angle and freezing tempera? ture on the mechanical properties of the sandstone, this paper uses the triaxial compression test method and theoretical analysis method to study the changing characteristics of the strength, internal friction angle and cohesion of sandstones without fracture and fractured sandstones with dip angles of 0°, 15°, 30° and 45° at frozen temperatures of -5 ℃, -10 ℃ and -15 ℃ under different confining pressures. The results show that the strengths of fracture-free and fractured sandstones increase nonlinearly with decreasing of freezing temperature, decrease nearly linearly with decreasing of confining pressure, and decrease with increasing of fracture dip angle; the cohesions decrease with the increase of the freezing temperature, and both the internal friction angle and cohesion have the tendency to decrease first and then increase with the increase of the fracture dip angle; and the internal friction angles of fracture-free sandstone and fractured sandstone with 0° and 15° dip angles all decrease with the increase of the freezing tempera? ture, the internal friction angle of fractured sandstone with 30° dip angle increases first before decreasing with the decrease of the freezing temperature, and the internal friction angle of fractured sandstone with 45° dip angle decreases first before increasing with the decrease of the freezing temperature.
Abstract：
In order to derive the influence patterns of confining pressure, fracture dip angle and freezing tempera? ture on the mechanical properties of the sandstone, this paper uses the triaxial compression test method and theoretical analysis method to study the changing characteristics of the strength, internal friction angle and cohesion of sandstones without fracture and fractured sandstones with dip angles of 0°, 15°, 30° and 45° at frozen temperatures of -5 ℃, -10 ℃ and -15 ℃ under different confining pressures. The results show that the strengths of fracture-free and fractured sandstones increase nonlinearly with decreasing of freezing temperature, decrease nearly linearly with decreasing of confining pressure, and decrease with increasing of fracture dip angle; the cohesions decrease with the increase of the freezing temperature, and both the internal friction angle and cohesion have the tendency to decrease first and then increase with the increase of the fracture dip angle; and the internal friction angles of fracture-free sandstone and fractured sandstone with 0° and 15° dip angles all decrease with the increase of the freezing tempera? ture, the internal friction angle of fractured sandstone with 30° dip angle increases first before decreasing with the decrease of the freezing temperature, and the internal friction angle of fractured sandstone with 45° dip angle decreases first before increasing with the decrease of the freezing temperature.
2021, Vol. 58 