岩体体积节理数(Jv)的现场测量方法评价

采用横观各向同性的流体饱和孔隙介质地层模型, 模拟了井中由点声源激发的声场. 计算出了井孔声场函数的全部极点, 发现最低阶泄漏模式波极点的虚部与正常模式波极点的虚部大小属于同一数量级, 因而是不可忽略的. 在算例中还发现, 伪瑞利波相速度的低频极限值不一定等于地 层横波速度. 计算了由极点留数对应的斯通利波、伪瑞利波和两种泄漏模式波的激 发频谱和时域波形, 以及由割线积分给出的激发频谱和时域波形. 通过与全波的比较, 发现在一些情况下仅由准横波割线积分不能获得准横波首波, 必须将泄漏模式波与准横波割线积分波叠加后才能得到准横波首波, 泄漏模式对全波的贡献不能忽略.

EVALUATION OF IN - SITUMEASUREMENTMETHODS FOR COUNTING VOLUMETRIC JO INTS OF ROCKMASS

Rock mass volumetric joint count is one of the most important indexes to evaluate the integrity of rock mass. In - situ measurementmethodsmainly include directmeasurementmethod, spacingmethod, and joint num2 bermethod. All of these measurement methods, p rincip les and their respective disadvantages are analyzed in the paper. Combined with p ractical examp les, it is believed that directmeasurementmethod is relatively accurate, but it requires adequate measurement area that is as large as possible. Data coming from spacing method are slightly low, so it has to be multip lied by correction factor of 1. 05～1. 1; Joint numbermethod is strongly influenced by the azimuth of the surveyed surface. In app lication, it requires enough samp les. Their average value is used as the car2 dinal number. It has to be multip lied by experience correction factor of 1. 4～1. 7.