轴向静载对红砂岩中应力波传播特性的影响试验研究

发布时间：2018-05-21 04:43

本文选题：岩石力学 + 应力波传播　；参考：《岩石力学与工程学报》2017年08期

【摘要】：由于开挖卸荷效应以及原岩应力的复杂性,围岩体承受的静应力大小具有动态变化特点。为了研究静应力大小对岩石应力波传播的影响,利用动静组合加载试验装置,对红砂岩长试件进行小扰动的应力波传播试验,试件轴向静应力分别设置为13个等级。通过应力波传播速度和幅值随传播距离、传播时间以及静应力的衰减规律,研究不同静应力条件下应力波的传播衰减特性。结果表明,相同轴压下,不同测点处应力波形状基本相同;不同轴压下,相同测点处应力形状变化较大,轴压越大,应力波尾部出现的拉伸波越大。随着轴向静应力的增加,岩石纵波波速呈"快速增加平缓发展急剧减小"的趋势,轴向静应力与单轴抗压强度之比?s/?c=30%和?s/?c=55%是其2个应力分界点。相同轴压下,应力波幅值随传播距离及传播时间都具有良好的指数关系;随着轴压的增加,空间和时间响应强度逐渐减小,幅值空间衰减系数和时间衰减系数呈"快速减小平稳发展急剧增大"的趋势。随轴压增加,相同测点处幅值随轴压衰减系数??s先减小后增大,离冲击端越近测点处的??s变化越敏感。
[Abstract]:Because of excavation unloading effect and complexity of original rock stress, the static stress of surrounding rock body has dynamic variation characteristics. In order to study the influence of static stress on the propagation of rock stress wave, the small disturbance stress wave propagation test was carried out on the long red sandstone specimen by using the static and static loading test device. The axial static stress of the specimen was set up to 13 grades respectively. The propagation and attenuation characteristics of stress wave under different static stress conditions are studied by means of the attenuation law of stress wave propagation velocity and amplitude with propagation distance propagation time and static stress. The results show that under the same axial pressure, the shape of the stress wave at different measuring points is basically the same, and the stress shape at the same measuring point changes greatly under different axial compression. The larger the axial pressure is, the larger the tensile wave appears at the end of the stress wave. With the increase of axial static stress, the longitudinal wave velocity of rock shows the trend of "rapid increase and slow development and sharp decrease". The ratio of axial static stress to uniaxial compressive strength is 30% and 55% respectively. Under the same axial pressure, the amplitude of stress wave has a good exponential relationship with the propagation distance and propagation time, and the spatial and temporal response intensity decreases gradually with the increase of axial pressure. The amplitude spatial attenuation coefficient and the time attenuation coefficient show the trend of "rapid reduction and steady development and sharp increase". With the increase of axial pressure, the amplitude of the same measuring point decreases at first and then increases with the attenuation coefficient of axial compression. The closer the point is to the impact end, the more sensitive the change is.
【作者单位】：江西理工大学建筑与测绘工程学院;
【基金】：国家自然科学基金资助项目(51664017) 江西理工大学青年英才支持计划资助江西省教育厅科学技术研究项目(GJJ160616)~~
【分类号】：TU45

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