Fellenius / Petterson
The simplest method of slices assumes only the overall moment equation of equilibrium written with respect to the center of the slip surface. The shear and normal forces between blocks Xi and Ei are neglected. The factor of safety SF follows directly from the following expression:
where: | ui | - | pore pressure within the block |
ci,φi | - | effective values of soil parameters | |
Wi | - | block weight | |
Ni | - | normal force on the segment of the slip surface | |
αi | - | inclination of the segment of the slip surface | |
li | - | length of the segment of the slip surface |
Literature:
Petterson KE (1955) The early history of circular sliding surfaces. Geotechnique 5:275-296.