Abstract: Based on the stress relief measurement data of Huaibei coalfield, the distribution law of in-situ stress in study area is obtained. The results point out that: the change trend of each principle stress all increase with depth, the optimal direction of maximum horizontal principle stress is NEE. According to spatial value relationship of three principle stresses, the type of Huaibei coalfield belongs to dynamic stress field. The data from evolution of stress field and focal mechanism solution show that it is a tectonic stress field in a horizontal compression located in NEE and horizontal tension located in NNW. Through the analysis of regional tectonic evolution, EW and NNE directions’ structures formed the earlier coalfield’s structure, SN and NWW directions’ structures formed the later. Meanwhile , reverse faults formed in early transformed normal faults. Different tectonic stages bring up the modern tectonic framework in Huaibei coalfield.

Key words: Huaibei coalfield, tectonic evolution, in-situ stress field, focal mechanism