"Among the oldest types of structures with which engineers have had to deal are those which serve to laterally restrain masses of earth, or to prevent earth embankments from assuming their natural angle of repose. This is necessary where space is limited or the natural slope would encroach upon other property. These structures, usually called retaining walls, are subjected to forces, both lateral and vertical due to the pressures exerted by the backfill material and any loads imposed on the backfill material. The first step in the design of the retaining wall is to determine the magnitude, position, and line of action of forces tending to overturn the wall or cause it to translate. This must be done in order that the laws of mechanics may be employed to design a structure which will fail neither physically nor in its ability to perform the work it is intended to perform.
The problem of determining the external forces acting on a retaining wall has been, and is at the present time, a difficult one. The reason for this difficulty in solving what appears to be such a simple problem, is the variable characteristics of soils which must be used in their natural state, as a structural material. In steels, a few properties such as the modulus of elasticity, the yield stress, and Poisson’s ratio are sufficient to describe most of its behavior under any loading condition. The number of properties needed for an understanding of the action of soils under load are unknown, are usually large in magnitude, and sometimes these properties may vary with climatic conditions.
The subject of determining the earth pressure on retaining walls has been treated extensively in the early engineering literature. Many theories have been developed by such scientists as Coulomb, Rankine, Boussinesq, and others. These early studies were largely analytical in nature with very little experimental background. Of the various theories advanced, those of Coulomb and Rankine have been accepted and at the present time are taught in Engineering courses dealing with the subject of earth forces, and are referred to in accepted engineering hand-books as the correct procedure for determining forces acting on retaining walls due to the pressure exerted by the backfill material. The equations of Coulomb and Rankine do not cover the case of external loading on the surface of the backfill material. Engineers designing retaining walls where external loading on the backfill material may exist, have either had to assume an equivalent surcharge or have had to resort to one of the graphical solutions based on the above mentioned theories. To assume an equivalent surcharge leads to solutions which are erroneous, and tend to give factors of safety which are much greater than generally used in the design of more easily analyzed structures"--Introduction, pages 1-2.
Carlton, E. W.
Civil, Architectural and Environmental Engineering
M.S. in Civil Engineering
Missouri School of Mines and Metallurgy
iv, 32 pages
© 1954 John Bay Heagler, Jr., All rights reserved.
Thesis - Open Access
Library of Congress Subject Headings
Retaining walls -- Design and construction
Earth pressure -- Mathematical models
Print OCLC #
Electronic OCLC #
Link to Catalog Record
Heagler, John B., "Horizontal pressures on retaining walls due to line surface loads" (1954). Masters Theses. 2205.