Engineering Rock Mechanics
48 In situ stress Figure 4.6 Hydraulic fracturing straddle packer system being lowered into a borehole during stress measurement ...
Methods OF stress determination 49 If the elasticity assumptions are made, we find that the stress concentration factors do not ...
50 In situ stress which may be used in the laboratory to determine the elastic properties directly at the site where the test wa ...
Methods OF stress determination 5 1 Figure 4.9 The CSIRO overcoring gauge. (a) The CSIRO gauge. (b) Installation of the gauge. ( ...
52 In situ stress gauge has either 9 or 12 separate strain gauges, in rosettes of three, so there is some redundancy in the meas ...
Statistical analysis of stress state data 53 stress components. Thus, the variability (expressed via the six standard deviations ...
54 In situ stress N N I A. Scalar mean E w I B. Tensor mean s S Tensor uI u2 u, trend u, u2 uI trend 1 18 10 000" A. 18 10 045" ...
The representative elemental volume for stress 55 UH = (a, + u3y2 OD = (ul - u3)/2 1 & Vector iatoric addition component of ...
56 In situ stress x a a 8 e (4 x a a c 5 e Inhomogeneous medium Homogeneous medium I I RE" Size 0 IIIIIIIIIIIII Size Figure 4. ...
Predictions OF natural in situ stress stutes based on elasticity theory 57 as the depth below the ground surface increases, due ...
58 In situ stress Axial strain, E, = &= 1. - Young’s modulus, E=% Ea , “a I “a Lateral strain. Poisson’s ratio. 1 “v Figure ...
Collated worldwide in situ stress data 59 and so V 6, =- 0” 1-v where OH = oH1 = oHp This relation has been known for some time: ...
60 In situ stress 3000 e, 1000- E I N e, (^2 2) 1500- VJ 0 e, g 2000 - 0" 2500 - T I I I I I 1 I N e, (^2 2) 1500- VJ 0 g 2000 - ...
Collated worldwide in situ stress data 61 500 ,^ I. k = -+ 0.5 i2 ... I! O .* 0 /' . I ; Australia 1; v United States VI' A Can ...
62 In situ stress would expect the highest ratios to occur very close to, or at, the surface because the vertical stress is zero ...
Reasons for high horizontal stresses 63 4.8.7 Erosion The possibility that erosion of the ground surface causes an increase in t ...
64 In situ stress high shear stresses can be present and result from tectonic activity. In Fig. 4.17, we illustrate the subducti ...
Effect of discontinuities on the proximate state of stress 65 could well be a good representation for rocks containing three mut ...
66 In situ stress +++++*~x*~x~c++++~uxx~%%~++++ ++++++*%xxxrr+++~~xxxx%k+++t+ +++++++?l%xxxr+++sxwxxk%++++++ +++++++%2xxxr+++*xn ...
Effect of discontinuities on the proximate state of stress 67 t Discontinuity filling E, - Young’s modulus of discontinuity fill ...
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