Sampling Effects in Soft Clay: An Update on Ladd and Lambe (1963)

The paper presents a review of the effects of sampling on the subsequent behaviour of soft clay. It takes for its starting point the classic paper by Ladd and Lambe in 1963 on this subject. The effects of perfect sampling, stress relief and of tube sampling are considered. Particular emphasis is placed on the effects of desaturation and gas exsolution, and of destructuring as a result of tube sampling strains. The benefits of sampling soft clays with a sampling tube of large diameter, thin wall, sharp cutting edge and no inside clearance, and of immediate extrusion and trimming of the sample, are emphasised. The dangers of improving only sample quality in design methods which rely on empiricism are highlighted.