The features of phase and group velocity were advanced by means of preparing samples with different shaping . the phenomenon of " cusp " in group surface of quasi - shear wave ( qsv ) was observed . the inversed velocity surface according to calculated elastic constants in real orthotropic media is consistent with practical measured velocity surface 用加工不同样品形态的方法给出了正交各向异性介质的相速度和群速度特征，观测到各向异性介质群速度面上的尖点现象，并用测试得到的正交介质的弹性常数进行了数学模拟，其波场特征与测试的速度面特征相符。
