3D Geostress Measurement By Sleeve Fracturing Technique And Engineering Application

Firstly, the main characteristics and limitations of the existing geostressmesasurement methods are comparatively analyzed, and the achivement of geostresstest is ummarized, then the author put forward the basic concept of3D geostressmeasurement by sleeve fracturing technique. The technique of3D geostressmeasurement by sleeve fracturing comprehensively analyzes in-situ stress, solutes thestress of the main cell and calculates stress of adjacent stratas neighboring the testingsite through the testing results of three fracturing boreholes in different planes. Theself-developed sleeve fracturing instrument can commendably prevent seepageproblem of crack liquid in the fracturing borehole, so the test result is more accurate.The technique of3D geostress measurement by sleeve fracturing was applied inSuntuan and Xutuan coal mine, including5testing sites involving18fracturingboreholes. The testing results show that there exists high tectonic stress in the twotesting coal mine area, and the direction of the maximum principal tectonic stresscoincides with the tendency of strata, the second principal tectonic stress direction isconsistent with the strata’s strike, in addition, little tectonic stress exists along thenormal direction of strata.Sperposing the main element of tectonic stress and gravitystress we can get the in-situ stress main element. After obtaining the comparativelyaccurate in-situ stress measuring result, the article also analyzed the influence ofin-situ stress on the mining faces and roadways.