Mass Stabilisation / DSM

Mass soil mixing is a fast and cost–effective method for the in–situ improvement of soft soils including clay, peat, and silt. The technique can also be utilised when dealing with saturated soils such as running sands.

Our process involves the injection of a wet cementitious grout under medium pressure whilst thoroughly mixing the soils using bespoke equipment designed in-house to create an entire block of improved soils at depths of up to five metres.

In addition to improving an entire block of material, other layout arrangements are also feasible such as construction of wall panels and shallow columns.

Binders can include cement (OPC), fly ash (PFA) and furnace slag (GGBS). The specific requirements for each situation are determined through design and trials prior to commencement of the works.

The method with some adaptation of binders can also be utilised to solidify contaminated soils, and therefore in a single process you can remediate these from an environmental perspective and also significantly improve their engineering characteristics.


Mass stabilisation is a versatile ground improvement technology for both civil engineering and environmental applications.  It offers:

  • In – situ improvement of soft soils with a resulting increase in bearing capacity and improved settlement characteristics.
  • Remediation by solidification of contaminated soils.
  • Construction of low permeability cut-off walls to control ground water migration.

The accuracy of the installation process is controlled through the use of instrumentation mounted on the excavator which records binder pressure and flow, and the GPS machine positioning system which guides the operator to undertake treatment to the required extents and depth.


Example applications

  • Temporary excavation support in very soft, loose soils particularly where ground water ingress is an issue.
  • Support below drainage and service installation in areas of weak or low strength soil. Control settlement within acceptable limits.
  • Increase in bearing capacity through the construction of a soil mixed transfer platform.
  • Below structures and retaining walls there is improvement of soft compressible soils at depth thus avoiding the requirement to excavate and replace.
  • Below roads and hardstanding the improvement of compressible soils supports high traffic loadings and controls settlement.
  • For use below floor slabs and foundations for lightly loaded structures.