In Problem 17.7 assume that the ties at all depths are the length determined in Part b. For the in situ soil, ' 2 =

In Problem 17.7 assume that the ties at all depths are the length determined in Part b. For the in situ soil, ϕ'₂ = 25°, γ₂ = 15.5 kN/m³, c'₂ = 30 kN/m². Calculate the factor of safety against (a) overturning, (b) sliding, and (c) bearing capacity failure.

Problem 17.7

A reinforced earth retaining wall (Figure 17.35) is to be 10 m high. Here,

Determine:

a. The required thickness of ties

b. The required maximum length of ties

Figure 17.35

unit weight, y, = 16 kN/m and soil fric- tion angle, = 34 Backfill: Reinforcement: vertical spacing, Sy = 1 m; horizontal spacing, Sy = 1.25 m; width of rein- forcement = 120 mm; f, = 260 MN/m; = 25; factor of safety against tie pullout = 3; and factor of safety against tie breaking = 3