STUDY ON THE SMALL CRACKS OF COVER STRATA AFTER THE COMBINED MINING IN THE THIN SEAMS

摘要

By using the continuous exploration system with multi-pipeline in the borehole, the failure carcass of cover strata (specially, the small cracks developing) after the combined mining of 16, 17 thin seams of the 4th mining block in Zhaopo Mine is explored. after that, the researching result is considered as the output and the testing result of rock mechanics parameters is considered as the verifying data, the back analysis is made with the conception of the point safety degree. The relative height of the crack developing is obtained. So, the evaluating of the safety of 16, 17 seams combined mining under the gob water with extreme distance is made and the mining has been safety. The scientific basis is provided for he evaluating of the mining safety with the similar conditions.