Open AccessHolographic in situ stress measurements
Author(s) -
Bass Jay D.,
Schmitt Douglas,
Ahrens Thomas J.
Publication year - 1986
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1986.tb05170.x
Subject(s) - borehole , geology , stress (linguistics) , holographic interferometry , rock mass classification , calibration , stress field , displacement (psychology) , holography , geotechnical engineering , optics , structural engineering , engineering , physics , psychology , philosophy , linguistics , quantum mechanics , finite element method , psychotherapist
Summary. A new instrument for measuring the in situ level of stress in boreholes has been developed. The instrument operates on the principle of locally relieving the stresses acting on a rock mass by drilling a small hole into the borehole surface and recording the resultant displacement field by holographic interferometry. Because the recording technique is optical, the entire displacement field due to stress relief is obtained. A description of the stressmeter, theory of the interferometric technique, data reduction methodology, and results of laboratory stress relief calibration tests are presented. In addition, we present results from a field deployment of the instrument in an underground shale mine in Garfield County, Colorado using a test borehole within a support pillar. Sufficient data were obtained to constrain five of six stress components at a shallow level of the test borehole, thereby demonstrating the viability of the holographic technique. The holographic stress‐relief data yield an approximate EW maximum horizontal stress direction By comparison with previous hydrofracture measurements of Bredehoeft et al. , our results indicate substantial stress‐relief near the pillar face, thus masking any relicts of the far‐field tectonic stress.