Effects of particle shape and gradation on the results of miniature DCP tests in sand

Miniature dynamic cone penetrometer (mDCP) tests were completed to investigate the general effect that particle shape and size gradation may have on penetration resistance. This testing provides preliminary results for planning purposes for a future testing program that will include full-scale dynamic cone penetrometer (DCP) testing on sands having varying physical properties and characteristics. Generally, the blow counts per increment became greater with increasing relative density for dry and moist sands, as expected. Angular sands increased the blow counts, whereas rounded sands yielded lower blow counts for the same relative density and grain size distribution. At high relative densities, the effect of particle shape was generally more pronounced than at lower relative densities for a specimen of given particle shape. Gradation appeared to have an effect for the moist specimens, although a defined trend was not observed. The moist specimens exhibited greater resistance penetration than did the oven dry specimens. Scale effects are discussed and considerations for future full-scale testing are identified.