Engineers Australia

Stabilisation of reactive subgrades by cementitious slurry injection – A review

A. Wilkinson, A. Haque, J. Kodikara, D. Christie and J. Adamson


Slurry Injection Stabilisation is a cost-effective method for the remediation of discrete sections of railtrack subgrade. It is generally applied to subgrade soils that experience fluctuations in strength and volume with varying seasonal moisture contents, thereby undermining the performance of the track. This technique involves the direct injection of cementitious slurry to the subgrade where it reacts with soil particles to enhance the strength and stiffness while decreasing permeability and plasticity.

The aim of the slurry injection operation is to expose as much volume of subgrade soil to chemically active slurry material as possible. The mechanics of slurry infiltration of the subgrade strata and the subsequent reaction of the cementitious additives within the soil mass are two distinct fields of study that influence the scale of subgrade improvement. These fields have been examined in order to develop a comprehensive account of the technical processes involved in the stabilisation technique. This should help the improvement of slurry design and injection procedures to suit site-specific subgrade conditions.