A hand cone penetration test (hand sounding) is a light form of soil investigation in which a rod with a cone tip is pushed into the ground by hand (or with a light sounding device). From the resistance the ground offers, one infers how firm and bearing-capable the subsoil is at various depths. It is the simple counterpart of the mechanical cone penetration test.
How it works
In a sounding, a rod with a cone-shaped tip is pushed vertically into the ground. The force needed to push the cone deeper is measured:
- High resistance — indicates a firm, bearing-capable layer such as sand
- Low resistance — indicates weak layers such as clay or peat
- Depth profile — by noting the resistance at each depth, a picture of the soil build-up emerges
In a hand sounding this is done by muscle power, so the depth that can be reached is more limited than with a sounding rig.
Applications
The hand sounding is used mainly for smaller projects and in hard-to-reach places:
- Extensions, garden houses, and light structures — to determine whether a simple foundation is sufficient
- Interior work — sounding inside an existing house or crawl space where no heavy machine can go
- Preliminary investigation — a first impression of the soil before commissioning an extensive sounding
- Determining foundation depth — how deep the bearing-capable layer lies
Points to watch
- The depth achievable is limited; for heavy construction or deep foundations a mechanical sounding is needed
- Often combine a hand sounding with a hand bore to obtain soil samples as well
- Have the results assessed by an expert before choosing a foundation
Related terms
- Soil investigation
- Foundation
- Hand auger
- Founding depth
- Bearing capacity
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