EFFECTS OF CONTAINER BOUNDARIES ON FREE-FIELD BEHAVIOR OF DENSE SAND SUBJECTED TO SHOCK LOADING.
Abstract
The effects of wall boundary friction and support conditions on the behavior of dense 20-30 Ottawa sand were studied in a nominal 2-foot-diameter by 4-foot-deep soil test container subjected to shock loading from a 2-foot-diameter by 65-foot vertical shock tube. Thirty static tests (25 stress-transmission and 5 stress-strain) were conducted. Twenty dynamic tests (13 with and 7 without membranes to reduce wall friction) were conducted in which soil stresses and velocities with depth were measured. In 16 tests, a wide flange beam support system was used; in 2 tests a polystyrene foam support was used for the sand; and in 2 tests a concrete support was used for the bin. Shock pressures to nearly 500 psi were used in the dynamic tests. Dynamic tests showed that if the wall boundary friction were eliminated peak-stress attenuations were about 25 percent at the 4-foot depth and generally predictable from theory. When wall friction was not reduced, the attenuation was nearly 80 percent. The stress-time history with depth was radically affected by support conditions. In particular, the WF support boundary reflected both decompression and compression waves; the concrete support, only compression waves; and the foam support, only decompression waves. For the rigid and yielding support conditions, the observed wave-propagation behavior could be reasonably predicted using Heierli's method-of-impulses solution for inelastic wave propagation. It was also shown that a trilinear approximation of the stress-strain load and unload behavior of the sand adequately predicted the observed stress wave velocities for all support conditions. Recommendations for use of the existing system and a proposed new system are outlined. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1967
- Accession Number
- AD0807738
Entities
People
- Richard Vaughn
Organizations
- University of New Mexico