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AMERICAN SOCIETY OF CIVIL ENGINEERS
INSTITUTED 1852
TRANSACTIONS
Paper No. 1192
EXPERIMENTS ON RETAINING WALLS ANDPRESSURES ON TUNNELS.
The most extended experiments relating to retaining walls arethose pertaining to retaining walls proper and the more elaborate oneson small rotating retaining boards. The results referring to theformer agree fairly well with a rational theory, especially when thewalls are several feet in height; but with the latter, many discrepanciesoccur, for which, hitherto, no explanation has been offered.
It will be the main object of this paper to show that the results ofthese experiments on small retaining boards can be harmonized withtheory by including the influence of cohesion, which is neglected indeducing practical formulas. It will be found that the influence ofcohesion is marked, because of the small size of the boards. Thisinformation should prove of value to future experimenters, for it willbe shown that, as the height of the board or wall increases, the influenceof cohesion becomes less and less, so that (for the usual dry sandfilling) for heights, say, from 5 to 10 ft., it can be neglectedaltogether.
The result of the investigation will then be to give to the practicalconstructor more confidence in the theory of the sliding prism, whichserves as the basis of the methods to follow.
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As, in the course of this investigation, certain well-known constructionsfor ascertaining the pressure of any granular materialagainst retaining walls will be needed, it is well to group them here.The various figures are supposed to represent sections at right anglesto the inner faces of the walls with their backings of granular material.In the surcharged wall, Fig. 1, produce the inner face of the wall tomeet the surface of the surcharge at 
. It is desired to find thethrust against the plane, 
, for 1 lin. ft. of the wall. Draw 
through 
, the foot of the wall, making the angle of repose, ...