Distribution characteristics and evolution process of in-situ stress field in Huainan Mining Area

A method of data conversion and validity verification between hydrofracturing and stress relief in-situ stress tests is proposed.84 groups of effective in-situ stress test data within the buried depth of 500-1 050 m in Huainan Mining Area are statistically obtained, and the in-situ stress distribution vector map is drawn.Combined with the geological structure characteristics and previous tectonic movements in Huainan Mining Area, the distribution characteristics and evolution process of in-situ stress field in Huainan Mining Area are regressed and analyzed.The conclusions are as follow the type of in-situ stress field in Huainan Mining Area is tectonic stress field as a whole, the magnitude of stress field is mainly high stress field, and locally it belongs to ultra-high stress field.With the increase of buried depth, the maximum and minimum horizontal principal stress and vertical principal stress gradually increase, and the increase range of horizontal stress is less than that of vertical stress.The type of stress field shows the trend of changing from tectonic stress field to self weight stress.The maximum horizontal principal stress direction of most measuring points in Huainan Mining Area is NEE-NW, and locally NW-SE.The direction of regional tectonic principal stress field mostly inherits NEE-EW during Himalayan movement, and locally retains NWW-SEE in mid Yanshan movement.The Cenozoic unconsolidated strata accumulated in coal measure strata, which determined the vertical stress.