温度变化对煤系砂质泥岩三轴压缩力学特性的影响

Effect of temperature changes on the mechanical properties of coal-serial sandy mudstone under triaxial compression

为分析温度对煤系砂质泥岩力学参数的影响,利用RMT-150B岩石力学试验系统和GD-65/150高低温环境箱,对煤系砂质泥岩在25~55℃下三轴压缩试验的力学特性进行了研究。结果表明,在试验温度范围内不同温度下煤系砂质泥岩的力学特性有一定程度的差异。随温度升高,峰值应力整体上呈降低趋势;峰值应变在20~40℃逐渐增大,在40~55℃减小;弹性模量随温度升高,在20~35℃逐渐减小,在35~55℃逐渐增大;变形模量随温度升高,在20~45℃逐渐减小,在45~55℃逐渐增大。

In order to analyze the effects of temperature changes on the triaxial mechanical properties of coal-serial sandy mudstone, the paper takes it as its sandy mudstone sample drilled from No. 1410（ 1 ） working face of Zhangbei coal mine under South-China Mining Group. For the purpose of our study, we have done the compress experiments with the specimen in the laboratory condition which is very similar to the spot rock samples in mechanical properties. In the said experiments, we have taken the hard-compressed strength of the mud- stone as standard sample, whose reasonable weight ratio in making the cement as a kind of participants is in a ratio among; sand （1100）, water（1520）, mudstone（473） and clay（131）, as is re- quired from the point of view of construction engineering. We have also studies the triaxial compressive mechanical properties of the sandy mudstone by using the RMT- 150B rock mechanics testing system and GD - 65/150 temperature range of the environmental chamber between 25 ℃ and 55 ℃. As a result, we have gained the average value of mechanical parameters under the three specimen each in accordance with its own particular temperature demand. And, then, we have managed to analyze the influence on the stress- strain curve, peak stress, peak strain, elastic modulus and deforma- tion modulus of the sandy mudstone under different temperatures. The study results gained from our experiments show that there do exist dif- ferences in the mechanical properties under different temperatures. Besides, with the increase of the temperature, the peak stress tends to decrease on the whole, even if they may have a different tenden- cies below and above 35 ℃, that is to say, a 1.78% decline from 25 ℃ to 35 ℃ and a0.8%,decline from 35 ℃ to 55 ℃. The peak strain has been found increasing gradually before getting to 40 ℃ , and a 2.2 % increase from 25 ℃to 40 ℃ , but then gradually decreasing, and a 14.2% decline from the temperature ranges between 40℃ to 55 ℃. As to the elastic modulus, it begins to decrease gradually before 35 ℃, a 5.94 % decline from 25 ℃ to 30 ℃. But since then the temperature begins to increase gradually, in an increase range of 18.3% from 35 ℃ to 55 ℃ . As to the deformation modulus, it can be found decreasing gradually before 45 ℃, a 21.8% decline in a range from 25 ℃ to 45℃ , but since then, it begins to increase gradually, a 39.2 % increasing rate in a tempera- ture range from 45 ℃ to 55℃ . We have also gained the fit equation that every mechanical parameter varies with the temperature, which can help to lay out the basis for the stability analysis of deep soft rock roadway at high temperatures.