Former RAF Airfield - Tangmere, Chichester

Client:Miller Homes (Southern)
Date: 2015-2016
Nature of works: Soil & Groundwater Remediation & Development Platform Preparation
Contract Value: £950K

Soilfix were contracted to carry out breakout, soil remediation and development platform preparation works at the former RAF Tangmere Airfield.

The Challenge
A 4Ha portion of RAF Tangmere has been redeveloped to a 125 unit residential housing scheme with private gardens.  Site investigations identified sub-surface macadam containing coal-tar bitumen, which presented a risk to the underlying Principal Aquifer from polycyclic aromatic hydrocarbons (PAHs).  The site also contained significant in-ground structures and asbestos containing materials including cement fragments, insulation board and lagged pipework below the site.

Our Solution
Soilfix implemented a sustainable and cost effective solution in conjunction with idom Merebrook, all in accordance with a Materials Management Plan (MMP) developed in accordance with CL:AIRE Code of Practice (CoP), including:

• Stabilisation/solidification (S/S) treatment of 4,100m³ coal-tar bitumen contaminated soils to reduce PAH leachability to below stringent leachate criteria;
• Additional S/S treatment of unforeseen areas of aviation fuel contamination;
• Targeted removal of asbestos lagged pipework as licensable works;
• Comprehensive breakout of slabs & sub-structures, processing majority to Type-3 specification for permeable paving below development roadways & external areas;
• Hand-picking of asbestos cement debris from made ground soils;
• Cut / fill reprofiling site to development platform levels, incl. lime stabilisation to achieve optimal moisture content; and,
• Construction of working platforms for vibro-piling operations.

In spite of numerous unforeseen encountered during the project, Soilfix completed all works in sufficient time to allow unimpeded progress of Miller’s construction programme.  Of the total 20,000m³ materials subjected to processing, only 785m³ of unsuitable material required disposal off-site, resulting in almost 95% materials recovery achieved.