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Last edited 18 Jan 2019
Ground improvement techniques
There are a number of ground improvement or ground modification techniques that can be used to stabilise or improve the condition of an area of ground before construction work takes place. This may be necessary to improve or modify the ground shear strength, stiffness, permeability, and so on.
Some of the most techniques include:
Grouting in civil engineering refers to the injection of pumpable materials into a soil or rock formation to change its physical characteristics. It is one of the ways in which ground water can be controlled during civil engineering works. Grouting is suitable where soil permeability would create a heavy demand on pumping or where ground conditions mean it may be economically inefficient to bore wells.
For more information, see Grouting in civil engineering.
Soil mixing improves soft clays, peats and other weak soils with a high moisture content. It involves mechanically mixing the wet soils with a dry cementitious binder to create soilcrete. This helps increase bearing capacity and decrease settlement.
Soil compaction produces an increase in soil density and a decrease in air volume without producing a decrease in water content. It can improve shear strength, stiffness, bearing capacity and stability, reducing settlement and frost heave. This may be necessary in the construction of bases for highways, embankments and so on, or to create a suitable level base for the construction of a building. Existing soil can be compacted, or layers of new soil can be compacted, taking a site to the required level.
For more information see: Soil compaction.
Vibro-replacement works by using a crane-suspended downhole vibrator to construct stone columns through weak soils, improving their load-bearing and settlement capacities. Another term that can be used for this technique is vibro stone columns (VSC).
For more information, see Vibro-replacement.
Geotextiles are typically made using synthetic fibres such as polyester or polypropylene which create a flexible and porous fabric capable of providing strength and stability. Geotextiles have the ability to reinforce, protect, filter, drain and separate, and many applications use them alongside soil, placed at the tension surface for strength purposes.
For more information, see Geotextiles.
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