Observations of borehole deformation modulus values before and after extensive heating of a granitic rock mass
An extensive campaign of in situ deformation modulus measurements was recently completed using a standard NX borehole jack. These results were obtained in a granite intrusive where spent nuclear-fuel assemblies and electrical heaters had raised the rock temperatures 10{sup 0}C to 40{sup 0}C above ambient. We present an analysis of temperature effects based on 41 preheat and 63 post-heat measurements in three boreholes. Using analysis of covariance statistical techniques, we found that the deformation modulus is affected by heat, loading direction, and position within the borehole. The analysis also uncovered a significant interaction between the effects of heating and loading direction. We used 123 measurements from the same boreholes to evaluate the "Draft Standard Guide for Estimating the In Situ Modulus of Rock Masses Using the NX-Borehole Jack" which was recently proposed by Heuze. In particular, we examined the criterion for screening measurements in those cases where contact between the jack platen and the borehole wall was incomplete. We found that the proposed screen appears to operate randomly on the data and is therefore ineffective. 3 figs., 1 tab.
- Research Organization:
- Lawrence Livermore National Lab., CA (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 59356
- Report Number(s):
- UCRL--91468; CONF-850671--10; ON: DE85008297
- Country of Publication:
- United States
- Language:
- English
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