Guildford Depot

Surrey

SUBCONTRACT WORKS PACKAGE

Old Landfill site up to 6m deep.
25,000 tonnes of non-haz and hazardous materials disposed off-site to recycling and disposal
22,000 tonnes of imported materials
70,000 m2 of geogrid / geotextile installed
16-week construction period

the problem

Guildford Borough Council wanted to build a new council depot to house various departments, primarily their waste collection service. They wanted to sell their old depot land for housing development and relocate to a new more modern facility. The sale of the land, funding the new build.

The site owned by them, and chosen, was an old landfill site that had been operated in the 1970/80s and since abandoned. Up to 6m of landfill, mainly domestic refuse waste capped with 1m of demolition waste was present on site. Site was also traversed by fragile sewer main.

Due to time constraints, an environmental waste permit was not considered feasible for the reuse of material on site. Hence all materials had to be recycled/disposed off-site and replaced with imported materials suitable for the enabling works for the future build.

The Solution

BIOGENIE Remediation UK Limited were engaged at an early stage with the Client, McLaren to assist with the design of the enabling works. This involved extensive trial holing for waste classification purposes and engaging closely with McLaren’s designer Link Engineering for the geotechnical design.

High Energy Impact Trials (HEIC) were carried out to ascertain suitability to alleviate problems with future differential settlement. Geogrid and geotextile design was included on top of the HEIC solution to achieve piling platform design and surrounding road design criteria.

BIOGENIE UK provided Remediation Implementation plans, Asbestos Management Plans, Logistic Management plans, Environmental management plans all to the satisfaction of Guildford Borough Council, using our supply chain base to achieve the most economical disposal and imported options.

BIOGENIE delivered the enabling works package including all sourcing, financing and installing all materials.

Due to the fragile sewer, a lightweight fill option to achieve design levels over the main was agreed upon, again BIOGENIE sourced and installed this.

BIOGENIE carried out all environmental monitoring during the works including asbestos and vibration monitoring to the fragile main to the satisfaction of Thames Water. Water monitoring was carried out to demonstrate that potential contaminants were not being mobilised during the works.

An original build programme of 16 weeks was delivered in 12 weeks due to careful planning of onsite resources and haulage requirements with the works completed under fixed price all risks contract.

This enabled McLaren to secure the follow-on build contract from Guildford Borough Council.