Retaining Wall Calculator

Retaining Wall Calculation:

\[ F = \frac{1}{2} \times \gamma \times H^2 \times K_a \]

Wall Height:

meters

Soil Density:

kN/m³

Soil Friction Angle:

degrees

Surcharge Load:

kPa

Active Earth Pressure Coefficient (Ka):

Lateral Force from Soil:

Lateral Force from Surcharge:

Total Lateral Force:

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1. What is a Retaining Wall Calculation?

The retaining wall calculation determines the lateral earth pressure acting on a retaining structure. This is essential for designing walls that can resist soil pressure and prevent failure.

2. How Does the Calculator Work?

The calculator uses Rankine's earth pressure theory:

\[ F = \frac{1}{2} \times \gamma \times H^2 \times K_a \] \[ K_a = \tan^2\left(45^\circ - \frac{\phi}{2}\right) \]

Where:

\( F \) — Lateral force per unit length (kN/m)
\( \gamma \) — Soil unit weight (kN/m³)
\( H \) — Wall height (m)
\( K_a \) — Active earth pressure coefficient
\( \phi \) — Soil friction angle (degrees)

Explanation: The calculation considers soil properties and wall geometry to determine the total lateral force the wall must resist.

3. Importance of Retaining Wall Design

Details: Proper calculation ensures structural stability, prevents wall overturning or sliding, and accounts for additional loads like surcharge.

4. Using the Calculator

Tips: Enter wall height in meters, soil density in kN/m³ (typical range 16-20 kN/m³), friction angle in degrees (typical range 25-35°), and any surcharge load in kPa.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between active and passive pressure?
A: Active pressure occurs when the wall moves away from the soil; passive when the wall moves into the soil. This calculator computes active pressure.

Q2: How does water pressure affect the calculation?
A: Water behind the wall significantly increases pressure. Proper drainage is essential in retaining wall design.

Q3: What safety factors should be used?
A: Typical safety factors are 1.5-2.0 against sliding and 1.5-2.0 against overturning.

Q4: When should a geotechnical engineer be consulted?
A: For walls taller than 1.5m, complex loading conditions, or poor soil conditions.

Q5: What types of retaining walls can this calculator be used for?
A: Gravity walls, cantilever walls, and other types where Rankine's theory applies.