Trial Pitting

Often referred to as trial pits, test pits or trial trenches, these are used for sub-surface site investigations and examination of the soil and groundwater.

Trail Pitting

Trial Pitting is used as part of geotechnical and environmental site investigations.

The ground conditions and soil composition must be established prior to the start of any construction project. This is in order to assess if the proposed construction is practical, and whether specific foundation designs are required.

Environmental samples can be recovered for contamination testing and Waste Acceptance Criteria (WAC) assessments. Geotechnical samples can be recovered for classification, compaction, and strength testing.

Trial Pitting is a quick, low-cost method to assess sub-surface ground conditions to typical depths of 2.0 to 4.5m below ground level.

For this, our specialist teams use two methods of excavating Trial Pits:

Machine Excavated Trial Pitting

Machine Excavated Trial Pits can be used if greater depths are required over a larger area. Using either a tracked 360° excavator or a hydraulic wheeled backhoe loader (JCB 3CX or similar), the ground conditions can be assessed quickly allowing samples to be recovered for laboratory testing, and in-situ testing to be undertaken.

Hand Dug Trial Pitting

Hand Dug Trial Pits are excavated using insulated hand-held digging tools generally to a maximum depth of 1.20m. They are ideal on small-scale Site Investigations for obtaining near surface soil samples, exposing foundations, and ensuring there are no existing buried services prior to drilling a borehole.

We provide an extensive range of ground investigation services. In order to discuss these services in more detail, please contact our specialist Stata Geotechnics team.

What are the advantages of Trial Pitting?

  • Trial pitting is used as a cost-effective and quick method to gain a basic understanding of the soil profile throughout a site.
  • Trial pits can be more effective due to the larger volume of ground that can be tested in situ.
  • Trial pitting can be useful to investigate buried structures, variable ground conditions and soil profiles over a site.