Engineering Rock Mechanics

426 Questions 8.7-8.10: rock masses

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for a 2-D analysis with uniaxial loading.
The equation is for two orthogonal fracture !n /
sets, where E is the modulus-of the intact
rock, 111 and h2 are the fracture frequencies of
the two sets, si,, si2, sfl, and sz2 are the nor-
mal and shear compliances for the fractures
in each set, and a is the angle between the
applied normal stress and the normal to the
first set.
The equation reduces for one set (i.e. h2 =
0) to

11

_-_ - + as:l cos4 a +

Em E

cos2 a sin’ a

and if we put s:l = s and si2 = ks, and then
rearrange, we obtain

rad I

I

fi

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-=- + hs cos2 a (cos’ a + k sin2 a)

Em E