CASE STUDY
EX-SITU SOIL STABILISATION FOR A CULVERTRENEWAL PROJECT
MOD LONGMOOR, JUNE 2016
CLIENT: MINISTRY OF DEFENCE AND RW LANGLEY
Industry: Civils
For civils industries, we offer a permanent and temporary Soil Stabilisation solution, for projects where large areas of ground material needs treatment, whithout having to remove material from site.
Application: Ex-situ
Our ex-situ application is for large, open projects where there is an on-goingrequirement for stabilisation, or sub-base material in large quantities and thereis space for the stockpiling of spoil material onsite.
EXECUTIVE SUMMARY
This case study illustrates the successful application of SMR through our Ex-Situ method, at theMOD Longmoor site in 2016. Overcoming saturated soil challenges, SMR offered an innovativesolution resulting in landfill reduction, carbon footprint savings, preserved delivery schedule,and high-quality reinstatement material.
PROBLEM STATEMENT
The Longmoor Site on the Surrey/Hampshire border had undergone many changes since itsacquisition in 1863, but the existing culvert was no longer effective and needed to becompletely replaced
R&W Langley, as the main contractor, had won the contract for the major culvert replacementand embankment stabilisation. However, upon commencement, discovered that the spoil wasretaining too much moisture and therefore unsuitable for the planned disbursement across thesite.
The existing saturated soil, with over 45% moisture content, posed difficulties in achievingeffective disbursement and reusability across the site. Around 3,500 tonnes of spoil materialneeded to be treated to reduce moisture content below 12%, and the project timeline wasalready constrained.
THE SMR SOLUTION
For this project, new material could have beenimported to meet immediate project requirements,with the existing soil being sent to landfill. However,this would add transport cost and increase theenvironmental impact of the project. Alternatively,the saturated material could have be left to naturallydry for longer onsite. However, this would significantlypush back the completion date, resulting in costlytime delays. Also, there would be no guarantee of apositive outcome, and the material could still need togo to landfill. Therefore, the main contractor, R&WLangley, turned to soil stabilisation specialists SMR(UK), to deliver a solution.
To address the challenges, SMR (UK) collaboratedwith Richardson Recycling to set up an on-siteprocessing plant. We stockpiled SMR Batch-Mix on-site and utilised a specialised Powertrack 800screener and mixer for this ex-situ process. Thisprocess significantly reduced the retained waterpercentage to below the required target. Over a 10-day period, a two-man crew treated all 3,500 tonnesof material with an optimal mix ratio of 4% SMRadditive. Compression test blocks were employed forquality assessment.
RESULTS
The treatment process yielded impressive results. Soil strength improved from 2.2 to 5.3Newton/m2 after 7 days, and further to 4.3 to 8.7 Newton/m2 after 28 days, ensuring stabilityand performance of the material.
BENEFITS
Landfill Reduction: Zero material was sent to landfill, avoiding tipping fees and extratransportation costs.
Carbon Footprint Savings: Batch-Mixing on-site minimized lorry movements, resulting in areduced carbon footprint.
Lorry Movements Reduction: Avoided approximately 4,000 additional lorry movements,reducing environmental impact and costs.
Delivery Schedule Preservation: The original delivery schedule was maintained, yieldingadditional opportunities.
Cost Savings: Despite processing costs, the project remained cost-effective due to eliminatedlandfill and transportation expenses.
CONCLUSION
By utilising Ex-Situ Stabilisation with SMR, the MOD Longmoor project successfully overcamesaturated soil challenges, resulting in environmental benefits, cost savings, and the delivery ofhigh-quality structural reinstatement material.
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