Sub Surface provide Trial Pits (aka Trial Holes) throughout the UK for Geotechnical and Environmental Site Investigations.

Trial Pits are a quick, low cost Site Investigation method to assess the ground conditions and for Foundation Designs, Contamination Analysis, WAC Testing, Soakaways, etc.

Our Geotechnical Engineer / Geo-Environmental Engineer on site will log the strata in accordance with BS EN ISO 14688-1: 2002 and BS EN ISO 14689-1: 2003. Taking disturbed samples at regular intervals of each strata for Contamination Testing and Geotechnical Laboratory Testing and undertaking in-situ field tests, such as hand shear vane strength tests and if required, in-situ density tests.

There are two methods of excavating Trial Pits…

Machine Excavated Trial Pits

Machine Excavated Trial Pits are the most common method of Trial Pitting, using a tracked 360° excavator or a hydraulic wheeled backhoe loader (e.g. JCB 3CX), generally excavating to a depth of up to 4.5m.

The ground conditions across a large area can be assessed quickly and they allow 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 underground services.

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

All Trial Pits will be backfilled with arisings, with the hand dug Trial Pits being reinstated if required and the machine excavated Trial Pits being mounded slightly to allow for any possible settlement.

Whom to Contact

If you would like a quote for Trial Pits (Trial Holes) as part of your Site Investigation or have any questions, please do not hesitate to contact your Regional Sub Surface Office.