Design Parameters
Wall Type
Earth Pressure Theory
Wall Geometry
Wall Height H4.0 m
Base Width B2.0 m
Batter Angle α0 °
Wall Friction δ15 °
Soil Properties
Friction Angle φ30 °
Unit Weight γ18 kN/m³
Cohesion c0 kPa
Surcharge q10 kPa
Wall Unit Weight γ_w24 kN/m³
Allowable Bearing qa200 kPa
Seismic
Horizontal Seismic Coeff. kh0.00
—
Ka (Earth Pressure Coeff.)
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Active Force Ea [kN/m]
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Overturning FS (≥2.0)
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Sliding FS (≥1.5)
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Bearing FS (≥3.0)
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Max Contact Pressure σ_max [kPa]
Factor of Safety vs Wall Height H [m]
Earth Pressure Formulae
Coulomb Active Earth Pressure Coefficient:
$$K_a = \frac{\cos^2(\varphi-\alpha)}{\cos^2\alpha\cdot\cos(\alpha+\delta)\left(1+\sqrt{\dfrac{\sin(\varphi+\delta)\sin(\varphi-\beta)}{\cos(\alpha+\delta)\cos(\alpha-\beta)}}\right)^2}$$Active Thrust: $E_a = \tfrac{1}{2}K_a\gamma H^2 + K_a q H$
Overturning FS: $FS_{ot} = M_R / M_O$ (resisting moment / overturning moment)
Seismic (M-O): $\theta = \arctan(k_h/(1-k_v))$, replace Ka with $K_{ae}$
Engineering Use: Suitable for preliminary design checks per AASHTO, Eurocode 7, and Japanese design standards. Coulomb's method is also used for setting boundary conditions in FEM models of embedded retaining structures.