淮北煤田地应力场分布特征及其构造演化研究

Distribution Characteristics of In-Situ Stress Field and Tectonic Evolution in Huaibei Coalfield

以淮北煤田的应力解除法地应力实测数据为基础,得到了研究区地应力变化规律。测量结果表明,各主应力均有随埋深增加而增大的趋势,最大水平主应力具有明显的方向性,其优选方位为NEE向。根据三个主应力量值的空间关系,确定淮北煤田原岩应力场属于大地动力场型。由区域应力场演化及震源机制解资料,反映了淮北煤田现今处于NEE向水平挤压和NNW向水平张应力的构造应力场之中。通过区域构造演化分析,煤田早期以EW、NNE向构造为主,晚期以SN、NWW向构造为主,并出现早期挤压作用下形成的逆断层转换为正断层现象,不同期次的构造运动奠定了淮北煤田现今的构造格局。

Based on the stress relief measurement data of Huaibei coalfield,the distribution law of in- situ stress in study area is obtained. The results show that： the change trend of each principle stress increases 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 is 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 have formed the modern tectonic framework in Huaibei coalfield.