Rankine Active Earth Thrust & Overturning FS
K_a = frac{1 - sinphi}{1 + sinphi}; quad P_a = frac{1}{2} K_a gamma H^2 + K_a q H; quad FS_{OT} = frac{sum M_{resisting}}{sum M_{overturning}} ge 2.0
Engineering Specifications & Method of Calculation
Verify structural stability against overturning moments and horizontal sliding forces for cantilever concrete retaining walls.
Retaining Wall Design Criteria
A retaining wall must maintain a factor of safety against overturning of at least 2.0 and against base sliding of at least 1.5 under full active backfill thrust and surcharge load.
Frequently Asked Questions
What is the active earth pressure coefficient Ka for φ = 30°?
For a friction angle of 30 degrees, Ka = (1 - 0.5)/(1 + 0.5) = 1/3 ≈ 0.333.