Development of a 1.22-m-diam dynamic air overpressure soil test facility

A large cold-gas-operated air overpressure test facility has been designed, fabricated, and installed at the U. S. Army Engineer waterways experiment station to test soil specimens 1.22 m in diameter and up to 5.03 m in length under static and blast-type loading conditions. A series of preliminary tests were conducted to evaluate the loading characteristics and overall performance of the facility and to compare results of uniaxial strain tests on dry sand with well documented and generally accepted results of tests on similar sand specimens conducted in a previously developed 12.70 cm diam uniaxial strain test device. Based on the results of these preliminary tests, the large air overpressure loader appears to function as required by the design specifications. Results of the tests conducted on dense sand specimens compared favorably with results of tests conducted on similar specimens in the 12.70 cm diam device. Results of tests conducted on loose sand did not agree as well as those from tests conducted on the dense sand.