THE BEARING CAPACITY OF LARGE BORED PILE IN COHESIONLESS SOIL

Abstract

Thai geotechnical engineers started using bored piles more than 40 years ago but only in Bangkok, the capital of Thailand in which the soil is strata consists clay and sand. Piling projects outside Bangkok still prefer driven piles than bored piles because of the low cost. Recently bored pile is extensively used, especially in downtown but the pile size is small. The large bored piles were used for the first time in Khon Kaen in which the soil is cohesionless. A 1.2 m diameter  bored pile with 40 m long was tested by static method. The frictions along pile shaft were measured by 21 vibrating wire strain gauges installed in pile and then compared with the frictions computed by various methods proposed in the literatures. The method developed by Davies & Chan gave the best fit. The results show that   and  should not be constant but should vary in direct proportion to strength of the soils around pile.