How Important is a Geotechnical Site Investigation? 

by | Aug 16, 2021

A geotechnical site investigation is to be carried out during the planning phase of a construction project, although it is often overlooked or given little attention. The investigation will reveal the properties of the ground, such as how much weight it can bear, how easily it is deformed and how porous it is. 

Geotechnical testing as part of a site investigation is incredibly important, that is, unless you don’t mind delays, subsidence and other ground hazards. In fact, according to the Institution of Civil Engineers, the greatest technical and financial risks to development occur within the foundations and the ground itself.  

A 2015 study discovered that 37% of all industrial building projects and 50% of commercial building projects suffer delays due to ‘unforeseen ground conditions’. The study also revealed that in the past couple of decades, subsidence has cost UK insurance companies over £400,000,000 in claims. All of this could be easily avoided with a geotechnical site investigation. 

This shouldn’t really be a surprise. The ground is crucial in any development. It supports the foundations to keep up the whole building! It also dictates many other things on the land, such as if the underlying geology and ground conditions have the potential for the land to become impacted by contamination in the future, which may make it an unsuitable site for the project. 

Geotechnical expertise 

So, with site investigations being so important, you’d think that developers always go to geotechnical experts like Borehole Solutions, right? Well, according to ICE, this isn’t always the case. Apparently only 20% of site investigations are carried out by a geotechnical testing expert. Are these investigations likely to follow the highest standards set out by BSI in BS 5930:2015+A1:2020? We don’t think they are. 

A holistic site investigation would consist of borehole drilling in several places, as well as many trial pits, appropriate to the size of the development. These, alongside testing for contamination and other ground investigations relevant for the proposed development, are the best way to avoid unforeseen costs in your development. It often isn’t enough to just drill one borehole or one trial pit and assume that it will give you a good representation of the whole site. It might seem obvious, but the more samples of data you can collect, the better chance there is that ground hazards will be identified. 

A recent survey discovered that site investigations take up a very small amount (Less than 0.3%) of the overall budget. The cost of fixing problems will often vastly outweigh the cost of a site investigation, which could have highlighted the potential issue before it was to arise. It’s far more cost-effective to spend money at the start and save money in the long run. 

Contact Us 

Geotechnical site surveys are vital in the early stages of any development to ensure the rest of the project can run as smoothly as possible. Borehole Solutions’ site investigations follow BS 5930 at a minimum to make sure they are of the highest standard. If you’d like to find out more about our geotechnical site surveys, then get in touch! Contact Borehole Solutions today on 01733 200501.