Mechanical properties of rock samples with a single natural weak plane after freeze-thaw action

The freeze-thaw cycle test and uniaxial/triaxial compression test were carried out on sandstone specimens with different structural plane angles, and the variation of sandstone strength with the structural plane angle of a single-group structural plane was studied. The results show that the strength variation law established by the single discontinuity theory is in good agreement with the uniaxial and triaxial test results, and that these can correctly reflect the strength variation law of sandstone. Under a certain cell pressure, the sandstone strength declines with the number of freeze-thaw cycles. Under a certain number of freeze-thaw cycles, the sandstone strength improves with the cell pressure. The strength difference of rock samples with different structural plane angles decreases with the cell pressure and freeze-thaw cycles. Sample failure modes vary with the structural plane angles. When 0 degrees < alpha < alpha(1), the rock sample undergoes splitting tension failure through the matrix and bedding plane, with a few shear cracks. When alpha(1) <= alpha <= alpha(2), the shear failure of sandstone occurs only along the structural plane. When alpha(2) <= alpha <= 90 degrees, the splitting failure of the rock sample occurs along the axis direction.

Automated summary

The study conducted freeze-thaw cycle and compression tests on sandstone specimens with different structural plane angles, revealing a certain regularity in the variation of sandstone strength. The increase of confining pressure and freeze-thaw cycles can affect sandstone strength, while sandstone with different structural plane angles exhibit different failure modes.