The Behavior of Shallow-Buried Cylinders. A Synthesis and Extension of Contemporary Knowledge

摘要

The available information pertinent to the behavior of shallow-buried cylinders is synthesized and extended to gain a better understanding of its use for improving the design of underground shelters. The theoretical and experimental data are examined to define the areas in which further research is needed. A failure plane analysis yields (1) the minimum depth of cover required for all of the surface load to be carried by arching, (2) the maximum percentage of surface load which can be carried by arching for any lesser depth, and (3) the relative deformation between the structure and the free field required to develop the maximum possible arching. For a shallowburied cylinder in a uniform granular soil field, the net arching is shown to be essentially zero. Because the net arching across the structure is zero, the effective load on the structure tending to induce failure is the surface pressure. Consideration is given to the possibilities of elastic and inelastic buckling in the roof caving and local transitional buckling modes. Evidence is cited which indicates that for depths of cover sufficient to provide radiation protection, and for relatively thin-walled cylinders, failure will normally be in the inelastic transitional mode where a local buckle develops at or near the bottom of the cylinder. (Author)