高温砂岩热膨胀系数变化规律试验研究

发布时间：2018-11-23 19:49

【摘要】：热开裂已成为地下高温岩土工程安全运行的主要威胁之一。以煤炭地下气化等地下工程中的砂岩为对象,通过试验对砂岩热膨胀系数在升温过程和保温过程中的变化规律进行了系统的研究。研究表明,升温过程中热膨胀系数随升温时间的变化规律呈反曲线函数关系,分为4个阶段:初期阶段呈下凹形;第2阶段基本呈斜直线上升,热膨胀系数增长率基本恒定;第3阶段呈现上凸形;最后,热膨胀系数增长率下降并逐渐平稳。保温试验过程中随着温度升高,试样热膨胀系数逐渐增加;但温度达到700℃后,试样热膨胀系数增加趋势明显减缓,趋于平稳,试样轴向高度变化速度降低。
[Abstract]:Thermal cracking has become one of the main threats to the safe operation of underground high temperature geotechnical engineering. Taking the sandstone in underground engineering such as underground coal gasification as an example, the variation of thermal expansion coefficient of sandstone in the process of heating and heat preservation is studied systematically through experiments. The results show that the variation of thermal expansion coefficient with heating time is a function of inverse curve, which can be divided into four stages: the initial stage is concave, the second stage is inclined straight line, the growth rate of thermal expansion coefficient is basically constant. Finally, the growth rate of thermal expansion coefficient decreased and gradually stabilized. The thermal expansion coefficient of the sample increases gradually with the increase of temperature, but when the temperature reaches 700 鈩，

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