关键词: 砂岩, 轴向应力, 应力波, 纵波波速, 传播特性, 幅值衰减

Abstract: To study the influence of static stress on propagation characteristics of stress wave in sandstone with large length-diameter ratio, impact test of small disturbance is conducted by dynamic and static combined testing system. The variation of stress wave, P-wave velocity and stress wave amplitude attenuation under different static stresses are obtained. Research results imply that stress wave curves of different test points remain approximately the same when static stress is constant; stress wave curves vary remarkably when static stress changes. Compressional wave and tensile wave both exist in the presence of static stress, and tensile wave increases with the increase of static stress. In addition, static stress has a great impact on P-wave velocity in a linear relationship, and P-wave velocity decays exponentially with propagation distance. Moreover, static stress also has obvious influence on stress wave amplitude. With the increase of propagation distance, the jump of stress wave delays gradually and stress wave amplitude tends to attenuate as wave energy is absorbed by sandstone fractures. The results suggest that static stress affects stress wave propagation in sandstone by changing the internal pores or fractures of sandstone.

Key words: sandstone, axial static stress, stress wave, P-wave velocity, propagation feature, amplitude attenuation