Associate professor, University of Kentucky, College of Engineering, Lexington, KY
The overcoring procedure for the determination of the magnitude and direction of underground in situ stresses, in a coal mine entry roof, is reviewed. For an isotropic rock, the direction of the principal lateral stresses can be computed directly from the stress-relief measurements of diametral deformation for the three axes of the borehole in the roof. However the computation of the magnitude of the in situ principal stresses requires that the Young's modulus of the host rock be determined. The degree of influence of anisotropy of the rock on the orientation of the principal lateral in situ stresses is also examined.
Paper ID: GTJ10797J