砂岩扩容过程中超声波衰减的实验研究

利用振幅谱比法对砂岩扩容过程中超声波衰减的实验结果进行分析表明:岩石存在裂纹稳定性传播与裂纹的非稳定性传播和宏观破裂过程;在前期研究三轴实验中横波速度极大值作为岩石应力门槛值的基础上,增添了横波的衰减系数的最小值,即品质因子的最大值作为新的判据.提出了裂纹稳定性传播阶段与裂纹的非稳定性传播阶段分界的特征是:横波的衰减系数、横波损伤因子、泊松比、体积应变曲线在该分界处出现拐点.将其归属于裂纹传播过程中具有局部贯通时破裂的特征,该分界点处在岩石的应力门槛值与抗压强度之间.此项研究结果具有广泛的应用价值.

Study on ultrasonic attenuation in the process of rock dilatancy by amplitude spectrum ratio

The experimental result of ultrasonic attenuation using amplitude spectral ratio for the process of rock dilatancy shows there are three processes in that the cracking of rock,crack stability spread, crack instability spread and macroscopical cracking.On the basis of the max-S-wave velocity as rock stress threshold during the heading triaxial test,this paper adds lowest-attenuation coefficient of S-wave, that is the max quality factor,as the new judgement.It puts forward the characteristic in dividing processes of crack stability spread and crack instability spread.The characteristic is inflexional in the curve of S-wave attenuation coefficient,S-wave damage factor,Poisson's ratio and volumetric strain.All of them vest in the character of macroscopical and part cracking in this paper.The dividing point is between stress threshold and compressive strength.The result of the research has its application value.