Direct shear tests were performed on a sand sample in a shear box of $6cmx6cm$ at three

different normal stresses. The test results are provided in Figure $4.$ While performing the direct

shear test, would you expect to see the top load pad move up or down or remain as it is$?$ Provide

justification for your answer. Determine the confining pressure and deviatoric stress combinations

needed to fail a CD triaxial sample of the same sand, such that the normal stress on the failure

plane of the triaxial test specimen is $8ksf.$ While performing the $CD$ triaxial test, would you expect

the volume of water in the volume change device to increase or decrease. Provide justification for

your answer. $k=1{10}^{-2}\frac{m}{s}$ and $G_s=2\mathrm{.}65.$ Assume identical drained failure envelop and same

relative density of the sand samples for both the test methods.

$10$

F$1$gure $4$: Direct snear test results