Geoharbour

Jet Grout Column

Jet Grout Column is a ground improvement technique that has been used in the construction industry for over three decades. It is a cost-effective and efficient way to improve the soil conditions and stability of a site prior to construction. This method involves injecting grout columns into the ground, which are then filled with concrete or other materials to improve the soil’s bearing capacity and reduce settlement. Jet grouting can also be used to create underground walls or barriers, which can be used for water control or as part of an underground structure. This method is particularly useful in areas where traditional excavation methods are not feasible, such as in soft soils or areas with limited access. Jet Grout Columns provide an economical solution for improving soil conditions prior to construction, and can help ensure long-term stability of structures built on the site.

  • One of the semi-rigid inclusion method
  • High-velocity water-cement paste is injected through the horizontal nozzle(s) of the rod, which breaks down the soil matrix. The jet erodes and mixes the in-situ soil with grout and upward rotates to form a mixture of soil-cement composite
  • Capable to improve wild range of soil types from gravel to clay
  • Suitable to construct in limited space / dense urban area, where unwanted effects are not preferred, without interrupting nearby existing structure due to lower vibration
  • Able to create large cement column without causing huge ground disturbances

Major types of jet grouting methods

  • Single fluid is most suitable with cohesionless soils
  • Double fluid is more effective in cohesive soils because of additional air jets that help displace subsoil and reduce friction, creating a larger column than a single fluid system
  • Triple fluid injects air, water, and grout simultaneously. Lower-velocity grout emerges from nozzles below the erosion jets (air+water). This separates displacement from grouting and produces a better soil-cement mix.
Source : Nikbakhtan et al., 2010

Jet grouting procedure                            

1.Drilling with water

2.Start high-pressure grouting

3.Execution of jet-grouting column (rotating and withdrawal)

4.Repeating for the next column

Source : Hayward Baker
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