Analysts of Sheet-Pile Bulkheads

The introduction of the deep-arch, steel, sheet-pile section in 1912 has gradually led to the construction of bulkheads of unprecedented height. During this development the designer has been confronted by serious difficulties because of the uncertainties as to the effective passive resistance of the ground and the interlock efficiency of the piles. Only since the end of the World War have large-scale experiments on these important questions -been made in the United States and Europe, the outstanding ones on passive resistance of soil being those by Professor E. h. O. Franzius in the hydraulic laboratory of the Institute of Technology, Hanover, Germany.

The exploration of the phenomenon of passive resistance of soil still being in its infancy, the present design of bulkheads is based on the convenient assumption that passive resistance of soil may be represented by static forces that vary linearly with the depth, irrespective of the magnitude of movement of the wall. The elastic behavior of the soil is thereby ignored. The object of this paper is: (1) To outline and to interpret the result of full-sized tests on a steel sheet-pile bulkhead,.particularly in regard to the effective, passive resistance of sand and the interlock efficiency of deep-arch sheet-piling; (2) to offer suggestions pertaining to a possible stress distribution in the passive prism between the wall and the surface of rupture; and (3) to present a new theory of the stability of bulkheads, which takes into consideration the elasticity of both wall and soil and which treats the problem as statically indeterminate.