A concrete retaining wall having a cross section as shown by Figure 25 is 20 ft high. The top of the wall is 3 ft wide, and the base of the wall is 6 ft wide. The backfill is a cohesionless soil and...

A concrete retaining wall having a cross section as shown by Figure 25 is 20 ft high. The top of the wall is 3 ft wide, and the base of the wall is 6 ft wide. The backfill is a cohesionless soil and is level with the top of the wall. The backfill soil has a unit weight of 116 pcf and an angle of internal friction of 36°. Use the criteria indicated by Figure 18(a) to determine the wall stability against overturning and sliding. Assume that the force from the retained backfill acts at an angle of 25° from the horizontal. To check sliding along the base, assume a coefficient of friction equal to the tangent of the angle of internal friction. Use the unit weight for concrete as 145 pcf.