升温过程中盐岩动力特性实验研究

Experimental research on dynamical properties of rock salt during rising temperature

利用超声波技术对盐岩进行了升温过程中(无侧压,温度为20～270℃)的动力学测试,分析了超声波波速、动弹性常数以及温度所导致的损伤变化规律。试验结果表明,随着温度升高,盐岩的超声波波速、动弹性模量和泊松比都有不同程度地降低,且呈现一定的规律性。试验过程中所观察到的现象和理论分析说明,盐岩的热损伤主要由矿物失水和晶间裂纹所导致,损伤变量和平行轴向相对裂纹密度随温度的升高而增大,但速度逐渐变缓,试验中未观察到温度对盐岩损伤的门阀值以及损伤愈合现象。

Because of the special mechanical properties of rock salt can be used for the energy storage and waste （radioactive and toxic wastes） disposal. But one of the properties of deep ground is ＂high temperature＂ and the temperature plays very important role of the rock salt mechanical properties, especially rising temperature. Testing with the Yingcheng rock salt during rising temperature （without confining pressure, 20-270℃） using ultrasonic wave. From the experimental data, the velocity of ultrasonic wave, the modulus and the Poisson＇s ratio of dynamics decrease during rising temperature, but their trend is different. Dynamical elastic modulus decreases fast and the dynamical bulk decreases slowly. The relation of the ultrasonic wave velocity and the dynamical modulus between temperature can be expressed by functions. Both of experimental phenomenon and the data reveals that, the thermal damage and the relative align microcrack density parallel to the axis of specimen evolution with the temperature, but the rate is attenuating when the temperature rising. There is no phenomena indicates the ＂critical temperature＂ and damage self-healing due to the temperature.