LLANELLI WELLNESS VILLAGE
PROJECT OVERVIEW
In March 2021, CJ Associates were instructed by Curtins on behalf of Bouygues to undertake a ground investigation at Llanelli Wellness & Life Science Village in Wales. The purpose of the GI was to provide ground data for the design of Llanelli Wellness and Life Science Village. The village will be the first development of its kind in Wales, creating a unique ecosystem that co-locates business, research, academia, health, and leisure within landmark infrastructure. The GI data will be used by Curtins to inform the designs of the associated buildings and infrastructure.
The GI scope designed by Curtins comprised cable percussion boreholes with rotary core follow-on, machine excavated trial trenches and trial pits, gas/groundwater level monitoring and sampling, in-situ CBR and soakaway infiltration tests, laboratory testing, and a factual report c/w AGS Data. The site has a contaminative land use legacy (iron works and foundries), with certain areas having a BDA site designation of Red. This designation required the implementation of decontamination units with strict H&S/PPE procedures.
The project manager from CJA undertook a site visit and used the information gained to inform the pricing with the inclusion of tracked excavators to create access routes, security guards, and a GPR crew to undertake a service c/w site mark-up given the high density of services at one area of the site.
During the tender process, the CJA team was able to offer advice to Curtins with respect to borehole construction and security risks at the site following the completion of similar schemes within the vicinity of the site. The contract risk with the GI was the presence of a significant thickness of granular material, and as such we constructed the boreholes with three strings of casing (250 mm, 200 mm, and 150 mm) and maintained a continual supply of water to maintain hydraulic head. All of the boreholes achieved their required depth with the holes allocated to rotary core follow-on lined with PWF size drill casing.
Soon into the fieldworks, we found that the depth to rock was greater than anticipated and thus required more cable percussive drilling than anticipated at the tender stage. We immediately notified Curtins, and timeously agreed on alternative drilling rates and arranged for the mobilisation of a second CP rig to maintain the drilling programme. The boreholes allocated to rotary core follow-on were reprogrammed towards the end of the contract to avoid any standing time whilst awaiting the CP pre-bores being completed.
We undertook the trial pits, soakaways, and CBR testing concurrently, thereby providing efficiencies with associated cost savings from the excavator that was used at these operations. The excavator was also used to undertake reinstatement in real time following completion of each borehole.
A number of boreholes were installed with a 50 mm ID standpipe following a strict installation procedure. The boreholes were retrofitted with a groundwater monitoring logger. Variable head permeability testing was undertaken during the post-fieldwork monitoring period.
Data from the fieldwork was issued to Curtins directly from the site, allowing for timely decisions to be made with respect to termination depths of boreholes along with installation design. A factual report complete with lab testing was produced and the data from site has been both comprehensive and reliable and allowed Curtins to progress their design within their agreed programme with Bouygues.
GENERAL PROJECT DETAILS
Location: Llanelli, Wales
Sector: Commercial
Client: Bouygues
Consultant: Curtins
Contract Value: £100,000
Services: Cable percussive drilling, rotary coring, trial pitting, soakaway (BRE 365), CBR testing
