Agencies that meet the criteria of Practice D 3740 are generally considered capable of competent and objective sampling. Note 1-The quality of the result produced by this standard is dependent on the competence of the personnel performing it, and the suitability of the equipment and facilities used. 3 The chain saw uses a special carbide-tipped chain. The chain saw has proved advantageous in sampling difficult soils, which are blocky, slickensided, or gravelly, or materials containing alternating layers of hard and soft material. Stress changes alone can cause enough disturbances in some soils to significantly alter their engineering properties. Usually the expansion is small in magnitude because of the shallow depth. This is the best available method for obtaining large undisturbed samples of very stiff and brittle soils, partially cemented soils, and some soils containing coarse gravel.Įxcavating a column of soil may relieve stresses in the soil and may result in some expansion of the soil and a corresponding decrease in its unit weight (density) or increase in sampling disturbance, or both. This method of sampling is advantageous where the soil to be sampled is near the ground surface. Undisturbed block samples are suitable for laboratory tests where large-sized samples of undisturbed material are required or where such sampling is more practical than conventional tube sampling (Practices D 1587 and D 6519 ), or both.
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