基于罗德里格矩阵的岩石各向异性波速表征与声发射定位优化

Rock anisotropic wave velocity characterization and acoustic emission location optimization based on Lodrigues matrix

  • 摘要: 为了探究岩石波速各向异性特征及其对声发射定位精度的影响,开展了大理岩与粉砂岩单轴压缩试验。单轴压缩过程中,大理岩几乎完全处于弹性阶段,平均波速保持基本不变,水平波速始终大于斜纵向波速,说明初始状态下纵向裂隙较少。粉砂岩在压密阶段,水平、斜纵向及平均波速均呈现增加趋势;在弹性阶段,水平波速及平均波速缓慢下降,说明该阶段岩石在纵向上已出现微小裂隙;在损伤阶段,水平、斜纵向与平均波速的快速减小表明裂隙已贯通。根据岩石不同方向波速演化特征提出了基于罗德里格矩阵的岩石各向异性波速三维椭球体表征方法,通过统计椭球体长轴与真实裂纹分布方位角,大理岩和粉砂岩波速椭球体77%以上的长轴方位角与裂纹方位角分布一致,说明该方法可应用于裂纹扩展预测。同时提出了结合各项异性波速演化特征的声发射定位方法,通过断铅试验确定该方法平均误差在大理岩中为1.89 mm,在粉砂岩中为2.76 mm,在两种岩石中本文方法相较于传统单纯形法和Geiger方法定位精度均提高了58%以上,验证了该定位方法的准确性。

     

    Abstract: In order to investigate the anisotropy characteristics of rock wave velocity and its influence on acoustic emission location accuracy, uniaxial compression tests of marble and siltstone were carried out. Before the peak, the marble is almost completely in the elastic stage, the average wave velocity remains basically unchanged, and the horizontal wave velocity is always greater than the oblique longitudinal wave velocity, indicating that the longitudinal cracks are less in the initial state. In siltstone compaction stage, the horizontal, oblique longitudinal and average wave velocity all show an increasing trend. In the elastic stage, the horizontal wave velocity and the average wave velocity decrease slowly, which indicates that the rock has a small fracture in the longitudinal stage. In the damage stage, the horizontal, oblique longitudinal and average wave velocity decrease rapidly, indicating that the fracture has been penetrated. According to the characteristics of rock wave velocity evolution in different directions, a three-dimensional ellipsoid characterization method of rock anisotropic wave velocity based on Lodrigues matrix is proposed. The statistical ellipsoid azimuth of the ellipsoid is consistent with the true crack distribution, and more than 77% of the long-axis azimuth of marble and siltstone wave velocity ellipsoid is consistent with the crack distribution, indicating that the method can be applied to crack propagation prediction. An acoustic emission location method combined with anisotropic wave velocity evolution characteristics is proposed. The average error of the proposed method is determined to be 1.89mm in marble and 2.76mm in siltstone by lead breaking test. Compared with the traditional simplex method and Geiger method, the positioning accuracy of this method is increased by more than 58% in both rocks, which verifies the accuracy of the proposed location method.

     

/

返回文章
返回