Discrete depth soil sampling with a direct push rig is generally completed using a soil sampler as shown in the figure. The soil samplers use a clear two foot polymer liner or brass sleeves installed in the sampler for sample collection. The sample liners are typically 1.1 inch diameter although a larger sampler (1-3/4 inch diameter liners) can also be used.
Continuous soil sampling is generally completed using a macrocore soil sampler. The soil samplers use a clear four foot polymer liner installed in the sampler for sample collection. The sample liners are 1-3/4 inch diameter.
The soil samplers work by driving the sampler and drive rods to the desired sampling depth. A cone shaped plug in the tip of the sampler cutting shoe is held in place by solid inner rods inside the sampler and drive rods. This plug keeps soil from entering the sampler. Once the sampler is driven to the sample depth, a drive rod is added to the top of the rod string without an inner rod. The rod string is then advanced about two feet (for discrete sampling) or four feet (for continuous sampling) to collect the soil sample.
The sampler and rod string is pulled to the surface using the direct push rig. The soil sample liner (polymer or brass) is removed from the sampler. The clear polymer liner is generally cut using a hacksaw. Teflon sheets along with vinyl caps are used to seal the soil sample.
The sampler is decontaminated and a new liner is installed in the sampler in preparation for the next sampling interval. The sampler and drive rod string is then advanced to the next sampling interval.