Jet Grouting

High energy erosion grouting technique for difficult and variable ground conditions.

Jet grouting incorporates high energy water or grout jet erosion and grout replacement techniques to achieve grout treatment of ground strata that will not facilitate permeation grouting techniques.  Ground conditions of mixed granular and cohesive soils, weathered rock and highly variable strata are often treated with Jet grouting where strength and stiffness improvement or deep cut-off to ground water/contaminant flow are required. 

The jet grout columns generally comprise a mixture of the original in-situ soil and a cementitious grout.  The material is commonly called solicrete and can have significant unconfined compressive strength.  It is also possible to incorporate bentonite into the grout mix thereby producing a low permeability and non-brittle soilcrete material.  

Relatively large diameter grout columns (typically 1,200mm to 1,500mm) are formed in-situ with a small diameter drill hole (typically 90mm to 120m) and so structural disruption can be minimised. This can be a major advantage with ease of access and the ability to improve soil conditions beneath existing structures.

One significant benefit of Jet grouting is that the erosion process enables formation of grout treatment in direct contact with the external face of existing structures such as perimeter pile or diaphragm walls and previously formed adjacent soilcrete columns.  This ability is critical where cut-off to ground water is required for basement slabs or deep base plugs to resist uplift and heave. 

With our significant experience and knowledge of numerous grouting, foundation and ground improvement techniques the CMW team can assess the effectiveness of jet grouting techniques and identify when this approach is the best solution.  We can then provide design, specification, testing and construction recommendations to help ensure optimised construction outcomes.