Field load tests were conducted on piles 20 cm in diameter in medium dense and dense sands. The piles were buried, jack-driven, or hammer-driven into the sands with depths of embedment from 4 m to 11 m, and loading cycles of 10- cm penetration were repeated until total settlement reached 5 to 9 pile diameters. Settlement of 1 to 1.5 pile diameters was required before the ultimate load was reached for the buried piles, whereas the required settlement for the diven piles was 0.1 pile diameter.During excavation of the test site after the pile load tests, the soil around the piles was observed, and undisturbed samples were obtained for laboratory tests. Detailed density measurements and grain size analyses on a block sample of dense sand directly below the pile tip showed that the sand underwent marked reduction in volume accompanied by considerable crushing of the particles, i.e., the dry density increased from 1.47 g/cm3 to a maximum of 2.0 g/cm3, and the minus 0.105 mm fraction increased from 17% to 65%.
