The excavation of trial pits is a simple, cheap and reliable method of investigating soils and weak rocks at relatively shallow depths or rockhead at shallow levels.
Trial pits are also used to investigate shallow foundations, services, made ground and areas containing voids. Soil infiltration rates can be calculated in trial pits to aid the design of soakaways.
Typically, trial pits are logged by one of our Engineers. This involves a visual inspection of the excavation in terms of its stratigraphy, geology, groundwater level, stability, excavability, etc. Samples are taken and the pit is photographed before it is backfilled with arisings and left slightly proud to accommodate future settlement. Depending on requirements, the excavation can be backfilled in compacted layers, using an engineered fill, and the surface reinstated.
Trial pits can be excavated by hand or machine. In either case the process is not without its dangers. We aim to eliminate the risks as far as possible. It is therefore our policy that no person should enter any trial pit unless it is properly supported with shoring or the sides are battered back sufficiently. Any potential risk posed by poisonous or asphyxiating gasses must also be eliminated.
"The former Stag Lane landfill site, although well located for the Isle of Wight 'Reality Energy Centre', has presented us with need to gain a better understand of the geoenvironmental needs for our development future. We have been very well aided and advised on this by Geotechnical Engineering Ltd, who have helped us to devise and carry out the necessary ground works to a quality and methodology acceptable to the Environment Agency and the planning authority. What has additionally impressed us is the proactive, 'can-do' approach from every member of their staff that has been involved. We will continue to work with them."
Ray Tucker, CEO, Real Ventures (IoW) Ltd