SMR Application: In-Situ Stabilisation  

Where: FIFA Football Training pitch, Cardiff  

When: December 2020-January 2021 

Problem

When the pitch was originally planned it was clear that the poor Geotechnical properties & a high water table could potentially cause issues. The client required 7,800m2 to be stabilised & for it to achieve a minimum of 5% CBR value and for the levels to be within +20mm & -30mm tolerances.  The original design planned prior to our involvement was a sub-base 280mm of 6F5 to achieve 5% CBR with a 210mm capping layer of Type 1.   The client wanted to reduce the amount of muck away and to re-use as much site won material as possible, hence our involvement.  

Solution

The initial soil analysis results showed a high moisture content of 50% + & it was clear that parts of the site was heavily waterlogged due to adverse weather conditions the area had faced in November 2020.  After reviewing our test samples, our suggested SMR design Method was to modify the existing spoil with a mix ratio of 3% of SMR binder, stabilising at a depth of 300mm, with a capping layer of Type 1 stone at 100mm. 

We did this by carrying out a single pass of SMR Proprietary Binder to a depth of 300mm. The Binder was rotavated into the existing ground before compacted with a 13-ton single drum roller.  The type 1 stone was then laid and compacted at a depth of 100mm. 

After 48 hours of the curing process, the ground was already showing that it had exceeded the requirement of 5% CBR with a reading of 6.79%. After 7 days of curing the ground was showing readings of 15.86%. 

Although we encountered continuous adverse weather conditions resulting in the host material being wetter and more unmanageable than anticipated, we persevered throughout, dealt with the inevitable delays and still achieved what we set out to achieve.  

Structural material for reinstatement.

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Benefits

By utilising our innovative SMR stabilising method, our client was able dramatically reduce the import and export of materials to site saving in the region of 300 lorry movements, this resulted in a saving of around 1200 litres of diesel, a saving of 2.51 tonnes of CO2 emissions. In addition, our clients were able to eliminate 5,700 tons of spoil going to landfill,  saving around 1200 litres of diesel.  

By utilising the SMR stabilisation method, our clients were able to reduce their carbon footprint and made substantial cost savings without impacting on the performance of the construction design. SMR UK successfully achieved our goals on this project, resulting in very satisfied clients.