ABSTRACT
With respect to piles in clay, the qb and τs may be correlated to the un drained shear strength at pile tip level (cub) and the average shear strength along
pile shaft (su) by qb = ωcubNc, and τs = αsu. The ω is a reduction factor that relates the ratio of the full-scale strength to the smaller sample strength, ω = 0.6~0.9 (Rowe 1972), or ω = 0.75 for bored piles in fissured clays (Whitaker and Cooke 1966).
