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NF P94-261 (PMT)

This solution for cohesive and cohesionless soils use theory from the French standard NF P94-261, where the bearing capacity of foundation soil is given by a formula:

It is recommended to use a safety factor FS = 3 when calculating the bearing capacity using this method.

Equivalent net limit pressure p_le^* is a geometric average of values of pressiometric limit pressure from the footing bottom to the depth of h_r.

Depth h_r depends on the type of load (design/service), the geometry of foundation and eccentricity of the load:

Bearing capacity factor k_p depends on the type of soil, geometry of the foundation (ratio L/B) and equivalent embedding depth D_e.

Equivalent embedding depth D_e is calculated as follows:

or:

Values p_LM,i for determining equivalent embedding depth D_e are measured between terrain and foundation bottom.

If D_e/B < 2 :

Calculation k_p for strip, circle or square foundation:

Calculation k_p for spread footing (ratio L/B)

Coefficients a, b, c, k_p0 and k_pmax depend on the type of soil according to the table:

Load inclination factor i_δ is calculated as follows:

If δ_d < π/4:

If δ_d ≥ π/4:

Literature:

NF P94-261