The Challenge
This project included a number of challenges including made ground contaminated with heavy metals, asbestos containing materials (ACMs) and deleterious materials, as well as working within a busy operational site interfacing with other contractors. The Client needed a viable enabling solution for a new warehouse extension that would minimise surplus soil volume and associated offsite disposal costs.
Our Solution
Soilfix worked with the Client and their consultant JBA Consulting to develop a Materials Management Plan under the CL:AIRE Definition of Waste Code of Practice to enable on-site reuse of excavated soils. Soilfix then implemented a remediation and enabling scheme which included:
- Controlled excavation of soils ,including use of a portable XRF analyser to identify elevated heavy metal concentrations. Verification of XRF data by laboratory analysis;
- Handpicking of ACMs from soils by trained operatives. Over 5 tonnes of ACMs removed and disposed offsite as hazardous waste;
- Screening to produce homogenous fines, separate unsuitable deleterious materials and win oversize concrete/brick for inert disposal;
- Placement of screened fines as a lower pile mat layer, with stabilisation using Ordinary Portland Cement (OPC) applied with a ‘dust free’ spread and mix tractor-towed unit;
- Plate load testing on stabilised pile mat. Specified CBR of > 10% achieved;
- Offsite disposal of surplus soils (non hazardous and inert only);
- Localised area of ACM pipe lagging removed as HSE-licensed work.
Soilfix completed site works on programme and within the Clients budget, allowing piling works for the proposed warehouse extension to commence as soon as Soilfix demobilised from site.
