A risk of sliding occurs if the design value of the force Hd resulting parallel to this surface in the direction of the displacement is greater than the design values of resistance to sliding Rs,d. It must be verified that the following condition is fulfilled:
In the drained state, the design value of the shear resistance must be calculated with the design value of the friction angle:
In the undrained state, the calculational base area A' is calculated. With the design value of the cohesion in the undrained state cu,d, the design value of the shear resistance is determined: