Table $1-$ Direct Shear test results.

$1,$ Please identify the erroneous result from the provided data and justify why it is

considered incorrect.

$2,$ Disregarding the erroneous result, proceed to calculate the cohesion and internal

angle of friction of the clayey sand based on the results available in Table $1.$

$3,$ Concerning the erroneous result, if the test were conducted again at the same applied

vertical stress, what would be the expected peak shear stress at failure?

$4,$ Provide a brief explanation of why dense sands dilate and loose sands compress

during a direct shear test.

$5,$ If a nearly identical sample of the clayey sand was tested in a triaxial apparatus with

a cell pressure of $120$kPa, estimate the major principal stress and the principal stress

difference at the point of failure