ABSTRACT
STANDARD PENETRATION TEST (SPT) The standard penetration test is the most widely used field test world-wide. It involves driving a 50mm outside diameter, 35mm internal diameter split spoon (barrel) sampler, length 675mm, into the ground at the bottom of a cased borehole by means of a 93.6kg sliding hammer falling 762mm on to the top of the boring rods to the end of which the sampler is connected. A trip-release mechanism and guide assembly are usually adopted to control the drop of the hammer, and an anvil at the lower end of the assembly serves to transmit the blow to the boring rods. Before testing, the hole must be cleaned out to the necessary depth, but with care taken to ensure that the ground at the bottom of the hole is not disturbed. Jetting should not be used for location, and the casing must not be driven below the level in the ground at which the test is to be conducted.
