In situ Stress Measurement in Kilometer-Deep Mine and Its Relationship with Minefield Fault Structure

Abstract

In view of the complicated geological stress structure and fuzzy distribution characteristics of a kilometer-deep mine, the KX-81 hollow inclusion stress relief method was used to test in situ stress in Shuanghe Coal Mine at the level of –1100. On the basis of the field test data, the 3D grid diagram of the principal stress distribution in the deep mining area of Shuanghe Coal Mine was drawn, and the relationship between the in situ stress distribution characteristics and the fault structure in wellfield was studied. Results showed that 1) the directions of σ1 and σ3 at each measurement point were horizontal, and the other principal stress σ2 was vertical. 2) The maximum principal stress value was 1.26–1.48 times of the self-weight stress value, indicating that the horizontal tectonic stress plays a leading role in the in situ stress of the mine. 3) The horizontal and vertical stresses at a depth of about 1090 m were estimated according to the theory. A comparison revealed that the theoretical values were lower than the field measured values. The area was found to be dominated by horizontal tectonic forces belonging to the dynamic stress field. 4) The direction of σ1 at each measurement point was 114.70°–124.72°, with an average of 120°. The direction was NWW-SEE. In accordance with the distribution law of the fault structure in the wellfield, the consistency between the wellfield geological structure and the measured direction of the maximum principal stress was analyzed and verified. The research results provide technical basis for deep well roadway layout and stability control and improve the scientific nature and reliability of surrounding rock control of high stress roadway in deep wells under complex geological structures.