Ground Developments Ltd

gdl-turbojet

Turbojet deep soil mixing is the combination of mechanical mixing and jet grouting developed by Soilmec Italy, and we are the only company in the UK to have invested in this technology and one of only two in Europe.

When compared with mechanical deep soil mixing, Turbojet DSM can be used in a wider range of soil types, and it can achieve higher rates of production and more effective mixing which results ultimately in a higher quality soil mixed column. Importantly, Turbojet DSM is very effective in high plasticity clay soils, where standard mechanical deep soil mixing techniques are not effective.

 

The Process

Grout is injected at very high pressure through a series of outlet nozzles blending soil as the mixing tool advances. High pressure cutting is effective in most soil types including problematic cohesive plastic clays. The mechanical mixing of grout and soil is achieved using a mixing tool featuring cutting teeth, blades and a mixing head. The type and configuration of tool is selected for project specific requirements and soil types.

Turbojet columns are 600mm – 2400mm diameter with a strength up to several MPa depending on soil types and binder design. Column depths of up to 25 metres are achievable.

We select the type of binder and application rate depending on soil type and project requirements. Grout mix selection is based on our geotechnical site investigations, laboratory testing and field trials and experience. Grout is batched using an automated GM30 grout batching plant featuring automated electronic weighing of up to three binder components, accurately controlled water injection and a series of high sheer mixer and agitator tanks. Grout is delivered to the mixing tool using a high pressure 7T600J triplex piston pump capable of delivering pressure up to 800 Bar (11,600 PSI). Grout pressure is fully variable, being selected depending on the soil types and the column mix design.

 

Benefits

  • Increases allowance bearing pressure
  • Controls settlement
  • Reduces soil permeability

 

Advantages over mechanical Deep Soil Mixing and our other deep ground improvement techniques

  • No “horizontal hydro fracturing (claquage)”
  • Less spoil on surface
  • No shock and vibration during columns installation.
  • Good mixing quality also in plastic clay
  • Precise diameter and extreme verticality
  • High production rate

 

Technical data

  • Columns diameter: 600 to 2400 mm
  • Columns depth: up to 25 m depending on column diameter and consistency