论文信息 - Influences of changes in mechanical properties of an overcored sample on the far-field stress calculation

Influences of changes in mechanical properties of an overcored sample on the far-field stress calculation

Abstract The concentration factors for the determination of far-field stresses have been calculated based on three-dimensional FLAC 3D simulated results. FLAC 3D is an explicit finite difference computer program. Three-dimensional numerical simulations have been conducted using FLAC 3D to determine the influence of altered overcored sample parameters on the far-field stress calculation. Both Young's modulus and Poisson's ratio are known to change during overcoring in highly stressed rock as a result of stress-relief damage. Modification factors have been proposed to take into account the influence of the reduction in Young's modulus on the far-field stress calculation. The influence of change in Poisson's ratio has also been analyzed. A method of determining a Young's modulus value suitable for use in the far-field stress calculation is described and the influence of reduction in Young's modulus of an overcored sample on the determination of the stress ratio (SR) in the RPR method is analyzed. Using the proposed modification, the in situ stresses for the Atomic Energy of Canada Limited's Underground Research Laboratory are re-calculated based on 21 deep doorstopper measurements. The re-calculation shows an increase in the trend of stress magnitudes versus depth in the URL.

P. M. Thompson | P. Thompson | R. Guo | R. Guo

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