【目的】在注蒸汽原位开采油页岩的过程中,油页岩的抗剪强度对注采井筒和采场的稳定性至关重要,同时岩体的抗剪强度又受温度的影响而变化。研究了不同温度和不同剪切角度下油页岩剪切特性的变化规律。【方法】利用蒸汽发生装置对油页岩进行加热,实验中蒸汽温度分别设置为100、200、300、400和500℃;对蒸汽作用后的油页岩进行变角剪切试验,剪切角度分别为45°、55°和65°.根据试验结果,计算得到油页岩的变角剪切参数和峰值剪切应变,同时对不同温度蒸汽作用后油页岩的剪切破坏特征进行分析。【结果】研究结果表明:1)蒸汽温度小于300℃时,油页岩脆性破坏特征明显,当温度达到400℃和500℃时,油页岩延性破坏特征明显;2)油页岩的内聚力随着蒸汽温度的升高先增大后减小,内摩擦角随着蒸汽温度的升高先减小后增大,抗剪强度随着剪切角度增大而减小;3)油页岩的峰值剪切应变随着蒸汽温度升高而增大,且剪切角的高角度变化对油页岩峰值剪切应变影响显著;4)油页岩的剪切破坏形式随着蒸汽温度的升高由贯穿破坏向组合破坏转变,且次生裂纹增多。

【Purposes】In the process of in-situ steam-assisted oil shale extraction, the shear strength of oil shale plays a crucial role in the stability of injection and production wells as well as the mining gallery.  Additionally, the shear strength of rock formation is influenced by temperature.  The variations in the shear characteristics of oil shale under different temperatures and shear angles are in-vestigated.  【Methods】 A steam generation apparatus was employed to heat the oil shale.  In the exper-imental setup, steam temperatures were set at 100, 200, 300, 400, and 500 ℃, separately.  Subse-quently, the steam-treated oil shale was subjected to variable-angle shear experiments at shear angles of 45°, 55°, and 65°.  According to the experiment results, the variable-angle shear parameters and peak shear strain of the oil shale were calculated.  Furthermore, an analysis of the shear failure charac-teristics of the oil shale following exposure to different steam conditions was conducted.  【Findings】The research findings can be summarized as follows: 1) At steam temperatures below 300 ℃ , oil shale exhibits pronounced brittle failure characteristics, while at temperatures of 400 ℃ and 500 ℃ , ductile failure characteristics becomes more evident; 2) The cohesion of oil shale first increases and then decreases with the increase of steam temperature.  Similarly, the internal friction angle decreases initially with rising steam temperature, followed by an increase.  The shear strength decreases as the shear angle increases; 3) The peak shear strain of the oil shale increases with steam temperature ris-ing, and high shear angle has a significant impact on the peak shear strain of the rock; 4) The shear failure mode of the oil shale transitions from penetrating failure to combined failure with an increase in steam temperature, along with an increase in secondary cracks.