Why should I Excavate Trial Pits?

by | May 17, 2023

Before you even begin thinking about starting a project, you first must determine whether construction is even possible! This might seem obvious, but you’d be surprised by how many structural failures we’ve seen due to people overlooking this. This requires digging trial pits to analyse the conditions and composition of the ground. There’s no reason not to – it’s straightforward, cost-effective and provides reassurance before construction work begins.

At Borehole Solutions, we’ve lost count of how many pits we’ve dug over the years. If you’re wondering why they are just as commonplace today as ever before, our expert team have the answers!

What are Trial Pits?

Unlike our other geotechnical drilling services, a trial pit is a simple concept to grasp. Trial pits tend to be between 1 and 4 metres deep, but more commonly around 2.5 metres below ground level. Should a larger pit be necessary, small diggers can also be used. Also, should the pit extend beyond 1.2 metres deep, structural supports must be installed within it. If the ground is unstable, the pit should always be reinforced, regardless of the depth. This is to ensure there is no risk of structural collapse should someone need to enter the area.

Should there be any underground features present, such as pipelines, the excavation must only be completed by hand. This can prove particularly useful when investigating buried structures and examining soil profiles within large sample areas. For more information about this, click here!

How can I Benefit from Pit Digging?

It’s all well and good understanding what pit digging is – after all, it’s a staple of the geotechnical industry. But what are the benefits of this technique? Some of the most prominent include…


When it comes to conducting a site investigation, no method is more practical than pit digging. With minimal, if any, machinery required, you’ll save considerably on transport and fuel costs. Also, as excavating trial pits is straightforward, it can typically be carried out in a single day.


Pit digging enables both disturbed and undisturbed samples to be collected. This permits a variety of sampling methods, including infiltration tests and contamination tests, to be facilitated. Upon excavation, a soil strata profiling test can then be carried out. The results of these tests are vital for potential contractors in determining the viability of projects.

Minimising Future Damage

As we’ve mentioned, pit digging is ideal for helping to locate the presence of any buried obstructions present on site. The last thing you want is to face the costly and time-consuming consequences of damaging any hidden buried cables or piping.

Contact Us

Trial pits are so much more than just a simple hole in the ground. If you’re interested in finding out more about pit digging, or any of our geotechnical drilling services, get in touch! To speak to the Borehole Solutions team, call us today on 01733 200501 or send an email to info@boreholesolutions.com.