Estimation of In-Situ Stress – Experiemtnal Trials on Kaiser Effect and Hydrofracturing Tests
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Professor, Mining Engg Department, National institute of Technology, Rourkela 563117 ,IN
Singam Jayanthu
Abstract
In the present paper, an acoustic emission trend in the Kaiser effect of rocks was studied and possibility of its application in the estimation of in-situ rock mass stress was explored. Several methods have been proposed for estimating in-situ stress in the laboratory from rock core samples collected from the boreholes. Among them, acoustic emission (AE) method based on Kaiser effect is the simplest. Conventionally, in-situ stress is estimated by plotting cumulative events versus stress. The change in the slope of the curve is an indicator of the Kaiser stress. In the present study, borehole drilled samples from five sites were investigated in the laboratory by AE method for which the in-situ stress was already measured by hydrofracturing method. A plot of cumulative events versus stress indicated three types of trend and is named as type 1, 2 and 3. It is easy to identify the Kaiser stress if the trend is of type 1. Types 2 and 3 trends do not show any perceptible change in the slope of the curve and it is impossible to identify the Kaiser stress. Since most of the samples showed type 2 and type 3 trend, to estimate the Kaiser stress, other AE parameters namely ring down count, energy and absolute energy of the events were used. Among these parameters, absolute energy plot showed more significant change in the slope, and hence preferred for identification of the Kaiser stress.
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References
Hardy, H.R., Jr. et al (1985): Recent Studies of the Kaiser effect in geologic materials, Fourth Conference on Acoustic Emission/Microseismic Activity in Geologic Structures and Materials, Proceedings of Conference held at Pennsylvania State University, October 1985, Trans. Tech Publications, Clausthal, Germany, pp 27-55.. 2. Hardy, H.R., Jr., and Shen, H.W. (1992): Recent Kaiser effect studies in rock, Progress in Acoustic Emission VI, The Japanese Society for NDI, pp 149-157.
Hayashi, M. (1979): Acoustic Emission to Detect Geostress,. Discussion paper in Thema 2, Proceedings of the Fourth International Congress for rock Mechanics, Montreux, Vol. 3. 66
Kanagawa et al. (1977): Estimation of Spatical Geo-stress Components in Rock Samples using the Kaiser Effect of Acoustic Emission. Proc. Japan. Soc. Civil Eng., 258: pp 63-75
Kanagawa, T., M. Hayashi, and Nakasa, H. (1976): Estimation of spatial geo-stresses in rock samples using the Kaiser effect of Acoustic emission, Proceedings Third Acoustic Emission Symposium, Tokyo, Japan, pp 229-248.
Lavrov. A. (2003): The Kaiser effect in rock: principles and stress estimation techniques, International Journal of Rock Mechanics & Mining Sciences, 40, 151-171.
Momeyez, M., and Hassani, F.P. (1992a), Application of Kaiser effect to measure insitu stresses in underground mines, 33rd US Rock Mechanics Symposium ( Tillerson and Wawersik), pp 979-987.
Momeyez, M., F.P. Hassani, and H.R. Hardy, Jr. (1992b): Maximum Curvature Method: A Technique to estimate Kaiser-Effect load from Acoustic Emission data,. Journal of Acoustic Emission, Vol. 10, No.3/4. pp 61-65.
NIRM, (2005): Laboratory method of estimating in-situ stress of rock mass by Kaiser effect, 89 , Unpublished Report
Pollock A A, (1989): Acoustic Emission Inspection, Metals Hand book, 9th Edition, Vol. 17, ASM International, USA, pp 278-294.
Ren, N.K. and Roegiers, J.C. (1983): Differential strain curve analysis-A new method for determining the pre-existing in situ stress state from rock core measurements, Proc.5th Conf. ISRM, Melbourne, pp F117-F127.
Seto et.al. (1998): In-situ stress determination using AE and DRA techniques, Int.J.Rock Mech. & Min. 35, No.4-5, Paper no.102
Simmons, G, R.W. Siegfried and Faves, M. (1974): Differential strain analysis: a new metod for examining cracks in rocks, J. Geophys. Res., 79,4383-4385.
Teufel. L.W. (1982): Prediction of hydraulic fracture azimuth from anelastic strain recovery measurements of oriented core, Proc.23rd U.S. National Rock Mech.Sym., Berkley, CA, pp 238-245.
Users manual, (2001), MISTRAS, AEDSP-32/16, Physical Acoustics Corporation, USA.
Wolter K.E. and Breckhemer, H. (1989): Time dependent strain recovery of the core from the KTB-deep drill hole, Rock Mech. Rock Eng., 22, 273-287.
Yamamoto, K., Kuwahara,Y., Kato,N.,and Hirasawa,T. (1990): “Deformation Rate Analysis for in Situ Stress Estimation from Inelastic Deformation of Rock Samples under Uni-axial Compression,” Tohoku Geophys. Joun. (Science Rep. Tohoku Univ., Ser. 5), 33, 127-147.
Yoshikawa, S. and K Mogi (1981): A new method for estimation of the crustal stress from cored rock samples: laboratory study in the case of uniaxial compression. Tectonophysics, 74, 323-339.
Yoshikawa, S. and Mogi, K. (1989): Experimental studies on the effect of stress history on acoustic emission activity - a possibility for estimation of rock stress. Journal of Acoustic Emission, 8, No.4, 113-123.
