煤层开采覆岩破坏的层析成像研究

用电磁波层析技术对邵武煤矿煤层开采后的覆岩破坏进行了探测，分析了吸收系数、介电常数和电导率的关系及数值范围，根据地质资料进行了综合解释．所得结果较准确地重现了地下结构的形态、裂隙带的位置和煤层开采后的变化过程，指导了对破碎带的成功堵漏，解决了生产中的一个难题．

GEOTOMOGRAPHIC RESEARCH ON CAP ROCK DESTRUCTION CAUSED BY MINING COAL SEAM

A new technique of crosswell electromagnetic tomography was adopted in a coal prospecting to detect the cap rock destruction caused by mining coal seam in Shaowu, Fujian Province, China. In this paper, some theoretical and technological problems are discussed regarding the propagation characteristics of radio wave under the ground, the value range and relationship among me medium absorption coefficient, dielectric constant and conductivity. Also, the authors comprehensively analyze these crosswell geotomograms based on some geological data and experimental test of rock samples.The logging data and geotomograms in two profiles distinctly reveal the geological features in the ground,the positions of fractured zones as well as the temporal variation in absorption coefficient before and after the production of a coal seam.According to the crosswell geological structure inferred from the geotomograms, the workers successfully once block up a fractured belt during their drilling, In contrast to it, in a long time they could not find a way out of this difficulty by the traditional techniques. Of course, It also finds out that there still exist some conflicts between geotomograms and drilling results.It is probably attributed to that the reflection correction and wave effects are not considered yet in the present image reconstruction.