动态扰动对不同含水率砂岩应力松弛影响的研究

Study on the Stress Relaxation of Sandstone with Different Moisture Contents Caused by Dynamic Distrubance

采用课题组自制的岩石松弛-扰动试验装置,研究了不同含水率砂岩的松弛过程动态扰动的影响,测试轴向应力、轴向应变的变化,观察到了砂岩试样在动态扰动后应变增加、应力降低的现象.根据试验数据,分析了松弛稳定后水对砂岩试样应力松弛量和应力松弛度的影响,基于岩石松弛扰动效应的本构方程,得到不同含水率扰动系数在2~6之间.结果表明:(1)由于水的影响作用,松弛稳定后砂岩试样的应力松弛量增加、应力松弛度增大,水对砂岩试样应力松弛衰减的影响作用增强;(2)在相同的冲击扰动能量作用下,含水率高的砂岩试样在动态扰动后应变增加和应力降低的现象更明显,扰动系数随含水率增加而增大.

mAxial stress and strain of sandstone with different moisture content were measured by self-designed stress relaxation-dynamic disturbance testing apparatus. It is showed that there exists stress decline and strain increase after the dynamic disturbance was applied on the sandstone specimen. Effects of moisture content on the stress relaxation magnitude and level were analyzed. According to the constitutive law of rock subjected to accumulated deformation disturbance,the disturbance factors range from 2 to 6 at different moisture content conditions. The results show that① During the stress relaxation process,the magnitude and level of stress relaxation at different time are increased due to the effect of water. The stress reduction can be enhanced by water.② Under the same impact energy,both the strain increase and stress decrease are observed in sandstone specimen under higher moisture level. The disturbance factor increases with the increase of moisture content.