Experimental Research on Viscoelastic Behavior for Saturated Rocks
详细信息
- 责任者：Xi Daoying (Mengcheng National Geophysical Observatory ; School of Earth and Space Science ; University of Science and Technology of China ; Hefei 230026 ; China) ; Xu Songlin
- 刊名：Chinese Journal of Geophysics
- 出版年：2011
- 卷期：54(9)
- 关键词：砂岩 ; sandstone ; 弹性 ; elasticity
- 页码：p.2302-2308
- 图表：illus., 20 refs.
- 分类号：1600
- issnNo：ISSN0001-5733
- isbnNo：CN11-2074/P
摘要
Experiments are performed by Metravib Dynamic Mechanical Analyzer （DMA＋450） under sine wave loading to simulate the seismic wave. The static load is fixed to 100N, and the dynamic load of the sine wave is 60N so that the total loading force is controlled under yield stress. Temperature is controlled between -50℃ and 125℃, and the heating speed is I℃ per minute. The frequency range is from 5 Hz to 1000 Hz. Pump-oil saturated arkoses and Pengshan sandstones are tested under uniaxial cyclic loading. The variations of attenuation, phase angle,modulus, and velocity with temperature or frequency are obtained. The attenuation peak and the phase angle peak shift to higher temperatures or higher frequencies when the frequency or temperature increases, which can be considered as thermal relaxation regularities. The increasing of attenuation with frequency can be explained by low-frequency resonance. The move of the attenuation peak and increasing of attenuation with frequency can be explained by damping. The aspect ratio of the micro cracks in rock samples would increase with the fatigue loading. The variation of aspect ratio can explain the phenomenon that the attenuation peak value decreases when the frequency increases and the peak shifts to higher frequencies. The experimental results and phenomena are similar to the low-frequency resonance standing wave experiments. Thus the thermal relaxation regularities generally exist for saturated porous rocks. The Youngrs modulus and velocity increase with frequency and decrease when temperature increases. There is obvious frequency dispersion, and the dispersion weakens when temperature increases. This investigation is very helpful to study of theoretical model and seismic data interpretation.