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为了研究高温对细砂岩力学性质的影响,对经历400℃~1000℃高温后细砂岩试样进行X衍射、电镜扫描及单轴压缩试验,分析了高温后试样矿物成分、结构特征及力学参数与温度的相关性。结果表明:高温后细砂岩试样内矿物发生了多晶转变,经历600℃以内高温试样内石英含量随温度升高增加,晶体衍射强度增强,600℃高温试样可观察到明显熔融和重结晶现象,超过600℃高温后试样内石英含量随温度升高降低,晶体衍射强度减弱,裂隙数量增多,裂隙宽度和长度有所增加,裂隙可分沿颗粒边界裂隙和穿过颗粒裂隙,600℃约为主要矿物石英变晶的临界温度;经历400℃~800℃高温后试样的纵波波速与温度呈线性降低;经历600℃以内高温对试样的强度具有强化作用,超过600℃高温后试样强度开始弱化,600℃可作为试样强弱转化的阈值温度;经历400℃高温后试样弹性模量、变形模量随温度升高稍有增加,初始模量和峰值应变基本保持不变。超过600℃高温后试样的变形参数随温度升高有所降低,超过400℃高温后峰值应变随温度升高单调增加,高温对细砂岩试样变形参数的影响较为敏感。
In order to study the effect of high temperature on the mechanical properties of fine sandstone, the XRD, SEM and uniaxial compression tests of fine sandstone samples after high temperature from 400 ℃ to 1000 ℃ were carried out. The composition, structural characteristics and mechanical parameters Correlation with temperature. The results show that the polycrystalline transition occurs in the fine sandstone samples after high temperature. The content of quartz in the high temperature sample under 600 ℃ increases with the increase of temperature, and the diffraction intensity of the crystal increases. The obvious melting and weight When the temperature exceeds 600 ℃, the content of quartz in the sample decreases with the increase of temperature, the diffraction intensity of crystal decreases, the number of cracks increases, the width and length of cracks increase, and the fractures can be divided along grain boundary fractures and through grain fractures. ℃ is about the critical temperature of the main mineral quartz crystal. The longitudinal wave velocity and temperature decrease linearly with the temperature from 400 ℃ to 800 ℃. When the temperature is within 600 ℃, the strength of the sample is strengthened. When the temperature exceeds 600 ℃ The strength of the sample begins to weaken, and 600 ℃ can be used as the threshold temperature for the transformation of the strength of the sample. With the increase of the temperature, the modulus of deformation and the peak strain remain basically unchanged after experiencing the elastic modulus at 400 ℃ change. The deformation parameters of the samples with the temperature higher than 600 ℃ decrease with the increase of the temperature. When the temperature exceeds 400 ℃, the peak strain monotonically increases with the increase of the temperature, and the high temperature is more sensitive to the deformation parameters of the fine sandstone samples.