RESPONSE OF HORIZONTALLY ORIENTED BURIED CYLINDERS TO STATIC AND DYNAMIC LOADING
Final technical rept. for Feb 1964-May 1965
ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS
Pagination or Media Count:
This was an experimental investigation into the response of small, shallow-buried in dense, dry sand and stiff clay, aluminum cylinders to static 15-min rise time, rapid 13 msec, and dynamic 0.3 msec plane-wave loading up to 500 psi. The cylinders had identical outside diameters of 3.5 in. and two thicknesses, 0.022 and 0.065 in. Hence, the cylinder stiffnesses, EICuR, were 1.7 and 45 dt 159 and 54, respectively. In stiff clay, the overpressure required to cause collapse increased very slowly with increasing depth of burial from zero to the deepest burial, three-quarters of the diameter. The hydrostatic buckling equation, Pcr 3 EICuR, was applicable for the cylinders tested. In the dense sand, the overpressure required to cause collapse increased greatly with increasing depth of burial from zero to one-eighth of the diameter. Below this depth it was not possible to collapse even the most flexible cylinders under the available 500-psi pressure. The hoop compression theory was verified. A ductility factor of about 7 was found to be conservative for cylinders buried at depths greater than one-eighth their diameter in the dense sand. The recorded strains were nonelastic in amny cases and it was shown that large yielding does not necessarily define collapse. Stress and moment were found to be nonlinear functions of overpressure, whereas thrust was generally found to be a linear function of overpressure. The differences between static and rapid loading in the elastic response of the cylinder were found to be small.