A slope 60 ft high has a face inclination of 30°. Uniform soils comprise the slope and foundation zone and have a unit weight of 115 pcf, an angleof internal friction of 25°, and a cohesion of 400...

A slope 60 ft high has a face inclination of 30°. Uniform soils comprise the slope and foundation zone and have a unit weight of 115 pcf, an angleof internal friction of 25°, and a cohesion of 400 psf. Use the Taylor stability charts for total stress analysis to:

(a) Determine the slope factor of safety in regard to soil cohesion only.

(b) Determine the slope factor of safety in regard to both cohesion and angle of internal friction. (Hint: Use a trial-and-error procedure by assuming a value for the FS to apply to ɸ, obtain a value for Ns , then compare the assumed FS with the formulacalculated FS.)