Definition - What does Trial Pit mean?
A trial pit can be defined as pits excavated at regular intervals along the proposed pipeline installation route in order to extensively study the sub-surface strata. These pits are also used to recover bulk soil samples where necessary. These pits are excavated in the ground that can support itself temporarily.
Based on reconnaissance and data and map study, location for in-depth or intrusive site investigation using trial pits and boreholes can be selected.
Trenchlesspedia explains Trial Pit
The selection for a trial pit should be such that a complete geologic sub-surface perspective can be obtained. At least three points should be selected at a spacing of 10-30 meters depending on site conditions and type of project. Commonly boreholes, probes and trial pits are used to undertake an in-depth investigation.
These pits are excavated in soils that can support themselves for the required time needed to conduct the investigation. In loose soil, shoring may be required. However; there is depth restriction in trial pits but the consequent area of ground that is disturbed is also quite large.
In environmentally sensitive locations, trial pits may not be permitted. The advantages are that it indicates vertical and lateral variations in the subsoil strata.