Thin-wall open-tube samplers (Shelby Tube Samplers) are used for soils that are particularly sensitive tosampling disturbance. They are suitable for fine soils up to a firm consistency, and free from large particles.
The sampler consists of a thin-walled steel tube whose lower end is chamfered to form a cutting edge. The area ratio is approximately 10%. The Shelby Tube Sampler gives good quality undisturbed samples in all finecohesive soils, including sensitive clays, provided that the soil has not been disturbed by sinking the borehole. Sample tubes are driven into the ground by a percussive method, using a Sliding Hammer. The Drive Head is manufactured with an NW rod female connection unless otherwise specified. The headhas an air-relief port and a simple arrangement for fixing the shelby tubes with 3 screws. Shelby Tubes are available in cold-drawn seamless carbon steel and in stainless steel. Usual diameters are 3" (76.2 mm) or 4" (101.6 mm) OD and the length of the tube is determined by the customer. When specifying the length of the tube required please allow an extra 100 mm for fixing the tube to the drive head. Please note that the cutting edge is thin and fragile and is likely to distort after some period of normal use. A refurbishment service is offered on used tubes. This sampler, often reffered to as a Shelby tube sampler, is the simplest and most widely used of the in situ quality samplers. We combined it with HSA technology, in soft, plastic soil conditions. The length of the sample between 0, 2 - 0, 5 m.