Ground pressure (Retaining Wall)

Last modified by Fredrik Lagerström on 2021/06/29 15:33

Calculation of the resultants position

For Earth pressure against the failure surface the required ground pressure resultant in order to achieve equilibrium is calculated. A moment equation around origin with a vertical and horizontal equilibrium equation results in the position y0, z0 and the slope α0 for the ground pressure resultant R0 and its components V0 and H0. Two combinations are considered, with and without surcharge load Q on the back fill situated between the wall rear and the failure surface.


For Earth pressure against the wall the procedure is similar. The part of the back fill and the load on it is considered partly by the earth pressures P1 and P2  and partly by the parts of the resulting force R in the rear slip surface that will affect the slab.

From this the ground pressure can be calculated.


Vertical ground pressure


The vertical ground pressure is assumed to be uniformly distributed on the surface b × l where:

  • l = length of retaining wall
  • b = effective width
  • b ≤ width of the foundation slabplattans totalbredd.

Bearing resistance capacity

The capacity is calculated according to [1] Annex D.

92997_-_flag_sweden.png Swedish Annex

The bearing resistance capacity is calculated according to [3] eqv. 4.2 and [5] 2.42 and 3.42. For cohesionless soil the calculation is performed for drained conditions (cohesion parameter c = 0). For normally consolidated clay the capacity is calculated with the assumption of un-drained conditions (friction slope ϕ = 0) while for over consolidated clay and medium soil the calculation is made with regard to both drained and un-drained conditions. For rock allowed values can be found in [5] 3.42. The partial resistance factor γR;v considering uncertainties in the analytical model is predefined for design approach 3 (see above).

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