Trial Holes are a quick, low cost Site Investigation method to assess the ground conditions and gain information for any underlying utility pipelines which may not have already been located.
The Bury Trial Holes project was a series of 90 trial holes across Bury to help assist with future new potable water mains rehab work for United Utilities. The total length of the new water project will cover approximately 11km, this will consist of replacing existing cast iron mains. The reason the mains require updating is due to the existing water mains causing a taste & smell issue within the Bury area.
All locations of each trial hole have been marked up previously by Amey, to show where they require each trial hole to be excavated. Each trial hole is hand dug as there may be other utilities present which should always be treated as a live asset. After every trial hole has been completed, data needs to be recorded on a log sheet document. This document records the information and lets United Utilities know the size, material, depth of main in the trial hole and any other information that may cause concerns when the new mains are installed (i.e. other utilities that could cause obstructions).
Each trial hole has a location plan which details the location and what information is required to document once the trial hole has been excavated. All the trial holes can be located on a overview/ area plan, which indicates all the trial holes locations. At P&H we have a strict procedure which must be followed for each trial hole, no excavation can be carried out without relevant and up to date utility prints from the client and a highways permit which indicates the dates of when the trial holes can be completed. An eCAT 4+ & Genny kit to be used on every excavation, with a survey conducted every 300mm depth. Hand dig only in footpath and machine excavating in carriageway.
Project Date: June to July 2021