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$20$ Marks Question #$2$

The following triaxial compression strength test results were obtained as the

result of a series of laboratory trials on core specimens recovered from a rock

excavation $($i$.$e$.$ mine$).$

$8$ Marks

a$.$ Based on the information provided, determine the Mohr$-$Coulomb

parameters which can be estimated to establish the limiting compression

failure locus for this rock. These parameters should include strength

variables as well as orientation conditions $($i$.$e$.$ internal angle of friction and

failure angle values$)$;

$2$ Marks

b$.$ From the results of part $a,$ what problems appear to be evident from the

data that has been given?

$8$ Marks

c$.$ Using the Mohr$-$Coulomb empirical equation relating principal stresses at

failure, determine the minimum axial applied stresses that would need to

be applied during triaxial failure tests to induce shear failure when

confining stresses equivalent to $5,15,22\mathrm{.}5$MPa are also applied;

$2$ Marks

d$.$ How could one verify the accuracy of the results in part c$?$