For geotechnical soil serveys, WIHA uses a wheel-driven sounding truck (22 tons), a lighter wheel-driven sounding truck (16 tons) and when ground
conditions are soft, a light-weight caterpillar-tracked vehicle (13 tons). In the case of limited accessibility to the terrain, we use the Unimog
soundingtruck with it's restricted width and length. Using the Unimog, soundings can be executed up to 3.5 tons maximum total pressure; with anchoring,
soundings up to 10 tons total pressure are possible. Furthermore, there is the possibility to have soundings executed by a freestanding appliance.
These can be executed up to a maximum of 100 kN. All soundings by WIHA are executed electrically, following the specifications of NEN 5140. If required,
besides cone resistance, also frictional resistance as well as water tension can be measured and dissipation tests can be performed.
With the aid of the sounding equipment, unaffected-soil samples measuring 32mm in diametre and 1.0 or 1.5 metres in length, can be taken with the
so-called "Mostap" sample device.