EXPERIMENTAL STUDY ON SOIL-PILE-STRUCTURE INTERACTIONIN LIQUEFIABLE SAND SUBJECTED TO BLAST-INDUCED GROUNDMOTION

摘要

Vibration tests of a pile-supported structure in a liquefiable sand deposit were performed at BlackThunder Mine in Wyoming USA. Ground motions from large-scale mining blasts were used as inputmotions for the test structure. The test structure was constructed in an excavated 3m-deep pit and the pitwas backfilled with water-saturated sand. Accelerations of the test site, the test structure and one of thepiles were measured. Pore water pressures in the pit and strains of the pile were also measured. Vibrationtests were performed six times with different levels of input motions. The maximum horizontalacceleration recorded at the adjacent ground surface increased from 20 Gals to 1,352Gals as the blast areaapproached the test site. The excess pore water pressures also increased with the levels of input motionsand sand boiling phenomena were observed in the test pit. It was thus clarified that this vibration testmethod was very effective in verifying the soil nonlinearity including the liquefaction and the dynamicbehavior of the pile-supported structure.