, is extended to the surface and considered to offer full cohesive and frictional resistances throughout its whole extent, the construction of [Fig. 11] applies, and gives a thrust of 1 220 lb., practically the previous amount.
As mentioned before, in connection with [Fig. 24], this supposes sufficient tension in the mass to drag down the triangle,
. Suppose, now,
to be the face of a trench which will just stand unsupported for the height,
, when the cohesion along
,