Interactive Tool

Retaining Wall Settings

K_a = 0.333

P_a = 75.0 kN/m

P_a

Solved Problems

Example 1: Stability Check for a Cantilever Retaining Wall

Problem: A cantilever retaining wall has a total height H=5.0 mH = 5.0 \text{ m} (from base of footing to top of stem). The soil unit weight γs=18 kN/m3\gamma_s = 18 \text{ kN/m}^3 and angle of internal friction ϕ=30\phi = 30^\circ. The concrete unit weight γc=24 kN/m3\gamma_c = 24 \text{ kN/m}^3. Wall dimensions: Base width B=3.0 mB = 3.0 \text{ m}, Toe length 1.0 m1.0 \text{ m}, Heel length 1.6 m1.6 \text{ m}, Stem thickness 0.4 m0.4 \text{ m}, Base thickness 0.5 m0.5 \text{ m}. Calculate the Factor of Safety against Overturning (FSOTFS_{OT}) and Sliding (FSSFS_{S}). Assume coefficient of base friction μ=0.5\mu = 0.5.

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Example 2: Overturning Safety Factor (Passive Resistance Ignored)

Problem: A cantilever retaining wall supports level backfill with total height H=6.0 mH = 6.0 \text{ m} (base to top of stem). Active earth pressure is represented by an equivalent fluid pressure of 5.5 kN/m35.5 \text{ kN/m}^3. Determine the Factor of Safety against Overturning (FSOTFS_{OT}) if the total resisting moment about the toe is ΣMR=750 kN-m/m\Sigma M_R = 750 \text{ kN-m/m}. Ignore the stabilizing effect of passive pressure PpP_p on the toe.

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Example 3: Required Base Width to Eliminate Tension

Problem: A retaining wall is analyzed for bearing pressure on the soil. The resultant vertical force Rv=300 kN/mR_v = 300 \text{ kN/m} acts at an eccentricity e=0.6 me = 0.6 \text{ m} from the centerline of the base. Calculate the maximum and minimum soil bearing pressures (qmaxq_{max}, qminq_{min}) if the base width is B=4.0 mB = 4.0 \text{ m}. Will tension develop at the heel?

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Case Study 1: Wall Failure Due to Hydrostatic Pressure Buildup

Problem: Following heavy monsoon rains, a 4-meter-tall cantilever retaining wall enclosing a residential property violently failed by sliding and overturning simultaneously. Investigations showed the wall was structurally sound and designed correctly for the active soil pressure of the gravel backfill. However, the weepholes at the base of the wall were completely clogged with silt and roots. Analyze the mechanism of this failure.

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