Sampling of soft soils in Japan

Sampling methods for marine soft clay in Japan are presented. Two types of sampling methods are employed in the routine investigation: the core tube method and the drilling pipe method. To collect high‐quality samples, a thin‐wall tube sampler with a fixed piston, whose specification is strictly defined by the Japanese Geotechnical Society, should be used for soft cohesive soils. In addition to the conventional sampling method, three newly developed sampling techniques are introduced: the Marine Auto Sampler, a wire line‐type sampler, and a Laval‐type sampler.