What Is the Rankine Lateral Earth Pressure & Retaining Wall Thrust Calculator?
Rankine earth pressure theory predicts the lateral forces exerted by soil backfill against a retaining structure.
How Does the Rankine Lateral Earth Pressure & Retaining Wall Thrust Calculator Work?
Evaluates Mohr-Coulomb failure envelopes assuming zero wall-soil interface friction and planar failure surfaces.
Rankine Lateral Earth Pressure & Retaining Wall Thrust Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
K_a = an^2left(45^circ - rac{phi}{2}
ight), quad K_p = an^2left(45^circ + rac{phi}{2}
ight), quad P_a = rac{1}{2} gamma H^2 K_a
Rankine plastic equilibrium lateral earth coefficients for smooth vertical backfaces.
How to Use the Rankine Lateral Earth Pressure & Retaining Wall Thrust Calculator
- Enter wall height in meters, backfill unit weight, and internal friction angle.
Step-by-Step Example Calculation
4.5-Meter Cantilever Retaining Wall
Input Values:
retainingWallHeightM:4.5
soilUnitWeightKnM3:19
frictionAngleDeg:32
Worked Steps: Active coefficient K_a = 0.307; total active thrust P_a = 59.1 kN/m acting at H/3 from base.
Understanding Your Result
Shows active coefficient Ka, passive coefficient Kp, and total resultant thrusts per meter of wall length.
Factors That Affect the Result
- Backfill slope angle (surcharge) increases Ka; wall friction (Coulomb theory) reduces active thrust.
When Should You Use This Calculator?
- Cantilever retaining wall design, basement foundation walls, and sheet pile embedment calculation.
Assumptions & Limitations
- Assumes frictionless, vertical wall face and horizontal backfill ground surface.
Frequently Asked Questions
Calculation Accuracy & Reference Note
Standard geotechnical earth pressure model.