Pressure Distribution on a Buried Flat Plate Subjected to Static and Airblast Overpressures

摘要

The objectives of this study were to develop and represent the pressure distribution on the surface of a buried, simply supported flat plate subjected to static and airblast overpressures. The plate was 24 in. square and buried in dense, dry sand to a depth of one-half span, and subjected to static surface overpressures ranging from 0 to 75 psi and airblast overpressures at the surface ranging from 29 to 65 psi. The plate was instrumented with thirteen soil-stress gages to measure the soil-stress or pressure distribution, and a load cell was used to measure the total reaction of the plate. A surface represented by a third order polynomial was fitted to the experimental data to represent graphically the pressure distribution and to facilitate the computation of the value (force) of the volume under the surface so that it could be compared with the value of force measured by the reaction load cell. The results indicate that the load on the plate, for both the static test and the dynamic test for times when the comparison was valid, was considerably greater than the reaction. The static soil stress, represented in nondimensional form as the ratio of soil stress to overpressure, remains relatively constant during loading but increases during unloading. The dynamic soil-stress overpressure ratio, above a certain overpressure level, increases from below unity at the center of the plate to above unity at the supports, and the distribution and variation with time essentially remain the same. (Author)