工作面无线电波透视实测场强成像分析及应用

为提高坑透数据解释效果,通过对工作面无线电波透视磁场强度的理论分析与公式推导,表明在正常煤层范围,场强值的变化主要受观测点几何位置控制;而在观测点场强路径穿过地质异常区时,主要影响因素为地质异常区内路径长及电磁波能量吸收系数值。将场强值H与观测点路径长R的乘积命名为M,则正常煤层段M可视为常量,而在地质异常存在范围,M值显著降低。将工作面划分为若干小单元,进行M值层析成像反演,可求取工作面各单元M值,再除以工作面平均宽度,得到各单元格场强值,从而获得工作面实测场强成像图。张集矿探测表明,该方法较好地反映了工作面内地质异常区的平面分布情况,回采验证探测结果可靠。作为新的解释手段,正在实际坑透探测中广泛应用。

Imaging analysis of measured magnetic field intensity from radio wave penetration for coal face and its application

In order to get better interpretation effect, based on the theoretical analysis and formula deduction of magnetic field intensity from radio wave penetration for coal face, it is found that the variation of magnetic field intensity values are mainly controlled by the geometric positions of observation spots within the normal range of coal face, but are mainly controlled by the path length of geologic anomaly and the absorption coefficient of magnetic wave energy when the observation path of field intensity through the area of geologic anomaly. The product of magnetic field intensity H and its path length R can be named as M. Thus, the M values can be regarded as constant within the normal range of coal face, but will be greatly lowered within the abnormal range. The coal face can be divided into many units in order to carry out the computerized tomography inversion of M value; then the M values of every units will be acquired by the special software. Subsequently, with all of the inversion values divided by the average width of coal face, the image of measured field intensity for coal face can be gotten. The surveying results from Zhangji Mine had given clear geologic anomaly areas of coal face, which have been well testified by coal mining. As a new interpretation means，it has been broadly applied to radio wave penetration for coal faces.