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Extraction of Contaminated Soils Using
High Pressure Jet Grouting
The Need
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Removal of contaminated soil underneath
existing structures causes settlement. There is a need for a remediation technology that
eliminates this problem. |
The Technology
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The jet grouting by the triple rod system can
be combined with an on site remediation technology (e.g., soil washing). Jet grouting was
developed primarily for underpinning and/or excavation support. It is a ground
modification system used to create in-situ cemented geometries of soil (soilcrete). The triple rod system utilizes high pressure water (5,000 to 6,000
psi) shielded in a cone of air to cut and displace the soil to the surface.
Simultaneously, as the soil gets dislodged, tremie is discharged to fill the disturbed
area with a pre-engineered cement slurry.
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The water jet is surrounded by a
concentric collar of compressed air which concentrates the jet, particularly below the
water table. This high pressure water and air steam is designed to erode the surrounding
soil. This washes certain contaminants from the coarser grained soils. This medium also
serves as the source of the air lift system which displaces the spoil to the surface where
it would be collected at the top of the drill hole. The contaminated material (water and
soil) that comes out through the work pad is fed directly into a decontamination system. |
The Benefits
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The benefits of this technology lie in the
future reduction of structural settlement, and site access flexibility. The triple rod
system method can be done with small jet grouting rigs, if necessary, to access very
restrictive locations. In addition, very little contact of contaminated materials with the
surrounding environment occurs. Also, no initial lowering of possible high groundwater
table is necessary. This technology has the potential of targeting pockets of
contamination in otherwise deep inaccessible locations (such as under existing
structures). |
Status
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This technology has been recently
commercialized. |
Barriers
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This technology has yet to prove that it is
cost effective and time efficient i.e. productive. There might be a need for skilled labor
on site to oversee or supervise proper implementation. |
Points of Contact
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This technology is being jointly used in
Germany as an in-situ soil extraction and treatment pilot program by the following
companies: Keller Grundbau GmbH, S & I Schlammentwasserung GmbH & Company KG, WUE
Umwelt - Engineers GmbH. |
References
Grisham and Sondermann: 'Extraction and Washing
Contaminated Soils Using High Pressure Jet Grouting Techniques', Superfund '90,
Proceedings the of 11th Annual National Conference & Exhibition, 1990.
Disclaimer Statement
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Neither the Construction
Industry Institute nor Purdue University in any way endorses this
technology or represents
that the information presented can be relied upon without further investigation. |
BBA03/LHM
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