"In September 1990, the US Army Corps of Engineers (COA), Sacramento District, started Phase 1 installation work for an eleven mile long slurry cutoff wall in the flood control levee on the east bank of the Sacramento River south of Downtown Sacramento..."
"Geotechnical investigations after the high flood of the Sacramento River in 1985 and 1986 concluded that a cutoff wall would be required to control seepage and to prevent sudden levee failure due to piping during flood conditions" Case History June 1-4 1993 International Geotechnical Engineering Conference.
SMW (soil mix wall machine) Equipment Positioning on Levee
"At the Sacramento Levee, a 3 auger machine was used for the majority of the cutoff wall installation, and a five auger machine was used in 1990 on the levee... The installation equipment consisted of a SMW machine for soil mixing, an automatic slurry plant for slurry production and delivery, and a backhoe for overflow control during cutoff wall installation." (see equipment in fig. above) The SMW technique is a soil improvement technology for modifying in-situ soils to construct cutoff walls... The technology consists of mixing soils in-situ with a slurry consisting of cement, bentonite, or other additives using multiple shaft augers to form column, panel, wall or lattice forms.. The soil mixing is carried out in-situ inside the bore holes made by 22-34 inch diameter multiple shaft augers."
"In 1990, COE decided to start the first two miles of levee modification work (phase 1)... The full production of cutoff wall reconstruction commenced in January, 1992 and was completed at the end of February using 2 sets of SMW equipment." Case History June 1-4 1993 International Geotechnical Engineering Conference by D.S. Yang, U. Lusher, I. Kimoto and S. Takeshima (1993) (note... one of the advantages of automated slurry wall construction is that you can use multiple machines and even do the levees on both sides of the river at the same time! r.c.m. 3/2/97)
Cross Section of Cutoff Wall and Levee in South Sacramento (installed in 1990)
To see color pictures of SLURRY WALLS produced using the backhoe method, click this text
I would like to thank Stephen Kashiwada (Deputy Director of the California Department of Water Resources) for mailing the report quoted above (along with several other articles on slurry walls) r.c.m. 3/2/97