Soil Bearing Capacity Calculator
Calculate ultimate and allowable bearing capacity of soil using Terzaghi's bearing capacity theory for shallow foundations.
Soil and Foundation Parameters
Enter the soil properties and foundation dimensions
Clay: 10-100 kPa, Sand: 0-5 kPa, Silt: 5-25 kPa
Clay: 0-20°, Sand: 25-40°, Silt: 15-30°
Typical range: 16-22 kN/m³
Results
Calculated bearing capacity values
Bearing Capacity Factors
Nc
0.00
Nq
0.00
Nγ
0.00
Ultimate Bearing Capacity
0.00 kPa
Allowable Bearing Capacity
0.00 kPa
Safety Assessment
Low bearing capacity - consider soil improvement or deeper foundations
Terzaghi's Bearing Capacity Theory
Mathematical formulas and theory behind the calculations
Ultimate Bearing Capacity Formula
qu = c × Nc + γ × D × Nq + 0.5 × γ × B × Nγ
Bearing Capacity Factors
Nc (Cohesion Factor)
Nc = (Nq - 1) / tan(φ)
Nq (Surcharge Factor)
Nq = e^(π×tan(φ)) × tan²(45° + φ/2)
Nγ (Unit Weight Factor)
Nγ = 2 × (Nq - 1) × tan(φ)
Allowable Bearing Capacity
qa = qu / SF
Where: c = Cohesion (kPa), φ = Internal friction angle (degrees), γ = Unit weight of soil (kN/m³), D = Foundation depth (m), B = Foundation width (m), SF = Safety factor, qu = Ultimate bearing capacity (kPa), qa = Allowable bearing capacity (kPa)