Stress variability and the design of the Aespoe Pillar Stability Experiment

摘要

An in-situ experiment is underway at SKB's Aespoe Hard Rock Laboratory, called the Aespoe Pillar Stability Experiment. The experiment requires detailed knowledge of the in-situ stress tensor and the rock mass deformation modulus. During the preliminary design of the experiment an in-situ stress program using overcoring and hydraulic fracturing was carried out in several boreholes. The results provided a range in stress magnitudes which impacted on the design of the experiment. To constrain the in-situ stress tensor and deformation modulus, detailed convergence measurements were carried out during construction of the experiment access tunnel. The results from these measurements indicate that the stress magnitudes and orientations, and the deformation modulus are well constrained.