关键词: 板岩, 冻融循环, 层理倾角, 弹性参数, 单轴抗压强度, 破坏类型

Abstract: To reveal the effect of freeze–thaw cycle on elastic parameters and uniaxial compressive strength of slate, uniaxial compression tests were conducted on slate specimens with seven types of bedding angles under six types of freeze–thaw cycle. The DX-40 low-temperature control box and DNS100 miniature control electronic universal testing machine were applied for tests. We analyzed evolution laws of five elastic parameters, uniaxial compressive strength, and failure forms. Experimental results showed that the elastic modulus, shear modulus, and uniaxial compressive strength decreased exponentially with increasing the number of freeze–thaw cycles. While Poisson’s ratio increased linearly with increasing the number of freeze–thaw cycles. Particularly, the uniaxial compressive strength firstly decreased and then increased with increasing bedding angle. It is found that there are three kinds of failure forms under uniaxial compressive stress. When the bedding angle was 0°≤?≤26.6°, shear failure occurred with a certain angle from the vertical axis. When the bedding angle was 26.6°≤?≤83.0°, shear failure occurred along the bedding plane. When the bedding angle was 83.0°≤?≤90°, splitting failure occurred along the vertical direction. On the basis of the single discontinuity theory proposed by Jaeger, an empirical formula of uniaxial compressive strength was established and further verified by experimental data, in which bedding angles and the number of freeze–thaw cycles were considered as control variables. Therefore, the effects of the number of freeze–thaw cycles and bedding angles on compressive strength of freeze–thawed transversely isotropic rock can be well simulated by the model.

Key words: slate, freeze–thaw cycles, bedding angle, elastic parameters, compressive strength, failure forms