i68
DOCK ENGINEERING.
result. For instance, without using the angle of friction, as in the pre-
ceding investigation, take the forces acting at the point, O, in hg. 91, and
resolve them along the plane of rupture, C F. Then equate them for
equilibrium. The coefficient of friction being tan p, we have
P (sin 0 + cos 0 tan p) = W (cos 0 - sin 0 tan p);
wk2 1 - tan d tan p
2 ‘1 -i- cot ^ tan p’
which, when 6 and p are angles such that Ô = -------------— -, is readily trans-
formable into
P= tan2
or>
wh2 1 - sin p
2 ' 1 + sin p'
Chaudy’s Theorem.*—The undoubtedly excessive values attributed to
earth pressure, in the preceding investigations, have led a French engineer
to approach the problem from a fresh standpoint, and to evolve a solution
which, despite its complexity, yields results more in accordance with prac-
tical observation.
A F D x E
B C
Fig. 92. Fig. 93.
M. Chaudy starts with the postulate that a pressure, Q, applied to the
surface of a mass of earth causes an oblique thrust, P, and the object of his
investigation is to hnd the amount of this thrust, and the angle at which
* Mémoires et Comptes Tendus des Travaux de la Société des Ingénieurs Civils de
France, Bulletin de Decembre, 1895.