Trial Pits & Boreholes

Trial Pits

Before any construction project takes place, the ground conditions and soil composition must be analysed to determine whether the proposed construction work is feasible or not. This is often done by excavating a trial pit, either by hand or more commonly, by machine. It’s a simple and cost-effective means of geotechnical site investigation that the Mick George Group can complete to certify the suitability of the setting prior to any project commencing.

Trial pits are commonly used to investigate shallow ground conditions and can be particularly useful where buried structures, variable conditions or contamination is suspected or needs further investigation.

What is a Trial Pit?

Trial Pits are pits of between 1-4 metres depth. For pits deeper than 1.2 metres, Building and construction regulations clearly state that structural measures must be put in place to ensure the safety of anyone who has to enter it. If there’s known to be any underground features (gas pipelines, electricity cabling etc.) then the means of excavation must be by hand and not by machine for safety reasons

Trial pits (or trenches) can be more cost-effective than boreholes but they cannot reach the same depth. Trial pits can also excavated relatively quickly.

Machine Excavated Trial Pits

Machine Excavated Trial Pits are one of the more common methods of Trial Pitting, using a tracked 360° excavator or a hydraulic wheeled backhoe loader, generally excavating to a depth of up to 4.5m.

This allows ground conditions across a large area to be assessed quickly and allows both the vertical and horizontal faces of the Trial Pit to be examined.

Machine Excavated Trial Pits are generally undertaken when the Clients requirements may include:

Hand Dug Trial Pits

Hand Dug Trial Pits are dug using hand digging tools generally to a maximum depth of 1.20m and are ideal on small scale Site Investigations for obtaining near surface soil samples, exposing foundations and locating any underground services that may be on site.

Hand Dug Trial Pits are generally undertaken when the Clients requirements include:

Borehole Drilling

There’s a variety of uses for a borehole that can benefit everybody from sciences and engineering to businesses and individuals. Borehole Drilling is the creation of a narrow, deep hole in the ground known as a borehole. There are several different methods to drill a borehole and the best method for drilling often depends on the location of the site itself. This is usually compressed air or drilling fluids.

The Mick George Group has extensive experience in completing both borehole and trial pit production, as part of any wider site investigations.