draw a line,
, parallel to the top surface. By [Equation (7)], the thrust on any vertical plane as
,
, ..., is null, and any tension and cohesion that may actually exist along any of these planes will be ignored. This is equivalent to supposing vertical cracks along these planes, which leads to an increase of the thrust and is thus on the side of safety.
The weights of the successive trial prisms of rupture,
,