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Rock Mechanics.pdf - Mining and Blasting

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APPENDIX D LIMITING EQUILIBRIUM ANALYSIS<br />

D.2 Calculation sequence<br />

The following sequence of calculations allows angles of failure <strong>and</strong> angles of break<br />

to be estimated using the equations derived above. For dry conditions, U = V = 0.<br />

If the upper surface is horizontal, = 0. Positive values of are as shown in Figure<br />

16.19. The equations listed also apply for negative values of . The sequence of<br />

calculations is:<br />

(1) Calculate K from equation D.4.<br />

(2) Let p2e = 1<br />

2 (p1 + ′ )<br />

Z2<br />

(3) Calculate<br />

c ′<br />

from equation D.16<br />

(4) Calculate a from equation D.14.<br />

(5) Calculate b from equation D.15.<br />

H2<br />

(6) Calculate<br />

c ′<br />

(7)<br />

from equation D.13.<br />

Calculate X from equation D.18.<br />

(8) Calculate Y from equation D.19.<br />

(9) Calculate the estimated value of p2 from equation D.17.<br />

(10) Compare p2 from step 9 with p2e from step 2. If p2 = p2e, substitute p2<br />

for p2e in steps 3, 4 <strong>and</strong> 5 <strong>and</strong> repeat the calculation cycle until the difference<br />

between successive values of p2 is < 0.1%.<br />

(11) Calculate b from equation D.20.<br />

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