Question

Your coworker was impressed with the efficiency you showed in the previous problem and would like to apply your methods to a project at a site with a sandy clay profile. Direct shear test results show a vertical pressure of 80 kPa and the shear stress at failure of 48 kPa. Present your recommendations to your coworker.

Answer 1

48 = C' + 80 tanФ

Step-by-step explanation:

Recommendations to my coworker

a) Note that there are two unknowns, C' & Ф in the equation, so minimum of two test readings are required to have correct equation of the failure envelope.

Given reading of coworker

σn = 80 kPa

τf = 48 kPa

∴ 48 = C' + 80 tanФ