To prepare a soil slope, proof roll the graded area with a vibratory roller weighing a minimum of how many tons or a sheepfoot roller exerting a compression of how many pounds psi on the tamper foot at least five passes in the presence of an Engineer?

• A. 6 tons; 200 psi
• B. 8 tons; 250 psi
• C. 10 tons; 300 psi
• D. 12 tons; 350 psi

Answer: (B)

Proof rolling is done to verify that the graded area has achieved adequate density and to uncover any soft spots that could lead to instability on a slope. Using a vibratory roller with a minimum weight of eight tons or a sheepfoot roller that can exert at least 250 psi on the tamper foot ensures there is enough contact pressure to rearrange and seat soil particles without over-stressing the material. Requiring at least five passes helps confirm consistency and reveals any remaining weaknesses after multiple passes. Having the Engineer present ensures the process is performed to the project specifications and that any observed deficiencies are addressed before final approval.