Sampling tool used in the Standard Penetration Test (SPT) to measure its resistance. It is a thick-walled cylindrical steel sampler that:

• is split longitudinally into two halves

• can be opened to recover the soil sample inside

• is attached to drill rods and driven into the ground.

During the SPT:

1. The spoon is placed at the bottom of a borehole

2. It is driven into the soil by a 63.5 kg hammer falling 760 mm

3. The number of blows needed to penetrate 30 cm (after an initial seating) is recorded

This is the N-value, a key index of soil density/strength.