A sample of dry sand is tested in direct shear and a separate sample of the same soil is tested in a triaxial compression test. In the triaxial test, the confining pressure (or minor principal stress value) is held at 15 kPa, and the sample shears (fails) when the axial pressure reaches 51 kPa. What shear strength is expected for the sample tested in direct shear when the test normal (compressive) stress is 125 kPa?

A sample of dry sand is tested in direct shear and a separate sample of the same soil is tested in a triaxial compression test. In the triaxial test, the confining pressure (or minor principal stress value) is held at 15 kPa, and the sample shears (fails) when the axial pressure reaches 51 kPa. What shear strength is expected for the sample tested in direct shear when the test normal (compressive) stress is 125 kPa?