scope:

This test method describes the procedure, generally known as the standard penetration test (SPT), for driving a split-barrel sampler to obtain a representative soil sample for identification purposes, and measure the resistance of the soil to penetration of the standard sampler.

ASTM D4633 is necessary to measure the drill rod energy of a given drop hammer system, and using the measured drill rod energy, N-values can be corrected to a standard energy level.

Test results and identification information are used in subsurface exploration for a wide range of applications such as geotechnical, geologic, geoenvironmental, or geohydrological explorations. When detailed lithology is required for geohydrological investigations, use of continuous sampling methods is recommended.

Penetration resistance testing is typically performed at 1.5 m (5 ft) depth intervals or when a significant change of materials is observed during drilling, unless otherwise specified.

This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

The values stated in SI units are to be regarded as the standard.

Note 1-ASTM D6066 can be used when testing loose sands below the water table for liquefaction studies or when a higher level of care is required when drilling these soils. This practice provides information on drilling methods, equipment variables, energy corrections, and blow-count normalization.

The quality of the results produced by this standard are dependent on the competence of the personnel performing the procedure and the capability, calibration, and maintenance of the equipment used. Agencies that meet the criteria of R 18 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with R 18 alone does not completely assure reliable results. Reliable results depend on many factors; following the suggestions of R 18 or some similar acceptable guideline provides a means of evaluating and controlling some of those factors.