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Last updateFri, 24 May 2019 10am

Soil mixing provides engineered solution for housing project

Soil stabilisation and ground remediation specialist Deep Soil Mixing Ltd is for the first time using soil mixing solutions for foundations as an alternative to piling on a high quality housing project in St Mary's Bay, Kent.

The company's soil stabilisation techniques are being used for the first time across the whole site area under residential dwellings to prevent extreme settlements from variable ground. These works are shaving more than a year off the programme for a conventional 'Surcharge' solution as well as providing improved stability behind coastal defences for client Compass Builders Ltd.

The site is in an enviable position, close to a beautiful sandy beach with stunning views out across the English Channel and planning permission has been granted by Shepway District Council for the development which will be called ‘The Sands' on a brownfield site of a former hotel and military base which has been demolished. The scheme will consist of a range of 3, 4 & 5-bedroom houses and 1 & 2-bedroom apartments and will also include a new landscaped coastal park area, car park and children's play area.

Deep Soil Mixing Ltd has undertaken both column and mass mixing using their double rotary mixing head designed by Deep Soil Mixing Ltd Director Robert McGall, installing soil mixed columns to a depth of up to 10 metres as well as a soil mixed mattress across the whole of the site covering an area of just under 11,000m2.

The company has also used the cutter soil mixer on this project to install 200 soil mixed panels.  The Cutter Soil Mixer was specifically used on the St Mary's Bay project to overcome some isolated areas of very stiff layers of clay which had softer soils below so it was necessary to mix through the clay into the soils below to enable remediation to take place.  This is the fourth time this bi-rotational mixing head has been used in the UK. The previous three occasions were when Deep Soil Mixing Ltd used the cutter soil mixer on the Mersey Gateway Crossing in Cheshire, a retail park in Runcorn and more recently at Dover Harbour. 

Deep Soil Mixing Ltd's MD Robert McGall comments: "In response to a foundation enquiry from the client's consulting engineers Considine Ltd we put forward various options that soil mixing could provide to deliver a design solution that saved the client time and reduced cost comparable to alternative ground engineering solutions such as dig and cart away and piling. Deep Soil Mixing Ltd always advise getting involved with clients and their designers as early as possible in their development process to create engineered solutions that offer real cost savings for projects including real benefits such as reduced vehicle movements and the efficient use of onsite materials on their projects, which reduces the carbon footprint and offers environmentally friendly sustainable solutions.

Soil mixing was specified for use on this residential site to eliminate the differential settlement across the site. The alternative solution was to either pile the buildings which would have created huge conflicts in differential settlement or to remove soil from the site and take to landfill which again was not a cost effective or environmentally friendly solution. Soil mixing is also quieter than piling and has zero vibration which meant there was no impact on the surrounding residents."

The project is due to be completed later this year.