Purpose and Procedure: Direct-push sampling can be used to collect continuous, variably disturbed samples of fine to medium grained soils. In general, a continuous steel core barrel (core barrels vary in diameter and length) is advanced using hydraulic down pressure and repetitive impacts from a hydraulically-operated percussive hammer. As the core barrel is advanced, a soil core is collected inside of a lexan tube which lines the inside of the core barrel. The lexan liner (containing the soil core) is extracted from the core barrel and then split vertically to expose the soil sample for geotechnical classification and logging and laboratory sample collection.
Pros:
- Relatively fast and inexpensive to collect;
- Can collect a continuous sample;
- No drill cuttings generated (minimizes potential for contaminated soil cuttings).
Cons:
- Can result in the collection of size-biased samples of coarse-grained soils;
- Cannot sample effectively competent bedrock or very coarse-grained soils;
- Difficult to sample permafrost soils;
- No drill cuttings generated (for visual observation)
