Another Geotech Import: Deep Soil Mixing

Jasperse, Brian H.; Ryan, Christopher R.; ,

Another Geotech Import: Deep Soil Mixing

by Brian H. Jasperse, (M.ASCE), Group Mgr.; GeoCon, Inc., Pittsburgh, PA,
Christopher R. Ryan, Pres.; GeoCon, Inc., Pittsburgh, PA,

Serial Information: Civil Engineering—ASCE, 1987, Vol. 57, Issue 12, Pg. 66-68

Document Type: Feature article

Abstract:

A technique called deep soil mixing (DSM), imported from Japan, has been used to stabilize an existing dam foundation. When the Bureau of Reclamation discovered that Jackson Lake Dam had been built (in 1916) on soils that subject to liquefaction, they lowered the lake and decided to remove the 50 ft high hydraulic fill embankment and replaced it wwith an engineered compacted fill. Dynamic compaction was used to treat shallow parts of the foundation, but the very deep, loose soils were treated with DSM, which differs from jet grouting in two ways. The equipment is not high pressure, and the soil is mixed in situ, without excavation, by special paddles on the drilling auger. DSM columns were placed continuously to form an upstream cutoff wall and then in a hexagonal pattern to stabilize the foundation. DSM can also be used to prevent migration of contaminated groundwater, stabilize soils under water and create structural walls.

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