...inclinometers to measure slope change; piezometers to measure moisture and consolidation, and settlement plates to measure changes in elevation. Settlement plates are set every 300 ft, while inclinometers, piezometers and extensometers are installed at “pods” every 2,000 ft, Smith says.

Thompson Engineering, Mobile, Ala., and Applied Geomechanics Inc., San Francisco, are installing monitoring instruments, including multipoint bore-hole extensometers—also known as MPBX, or “spider,” magnetometers—to track settlement; inclinometers to measure slope change; piezometers to measure moisture and consolidation, and settlement plates to measure changes in elevation. Settlement plates are set every 300 ft, while inclinometers, piezometers and extensometers are installed at “pods” every 2,000 ft, Smith says.

Smith is eager to see the portrait of consolidation URS will be able to create with the data being collected. “It could give all engineers a better understanding of what geotechs are trying to tell them in reports,” Smith says.

The data will be available in March or April, when the contractor pauses for 90 days to allow consolidation and watch for strength gain, Smith says. “As soon as we get that, we can give Archer Western the go-ahead to reach the desired height.”

Archer Western began moving clay in August. It is on schedule, despite 16 rain days in that month alone. “It won’t be easy to place over 3 million cu yd of clay in 10 months, mostly through the hurricane season and winter, but we’ll make it happen,” Pospisil says.

Trucking Control

Although Archer Western’s contract includes about 120,000 cu yd of deep-soil mixing, two highway-crossing flood roller gates, two pump stations, four drainage structures with sluice gates and a complex sequencing of levee layers, the tough part is delivering the 3.15 million cu yd of clay needed for 7.54 miles of levee. “Our biggest challenge is making sure 25,000 cu yd can come to this job every day,” says Bill Heathcott, Archer Western program manger.

The contractor will deliver 730 truckloads daily from three pits to four areas of the project. To ensure profits aren’t dropped on the way and due to the geotechnical sensitivity of the rapid-consolidation project, Archer Western and the Corps will track the origin and placement of every bit of material.

The pace of the project is unprecedented, Heathcott says, adding, “How do you get this much material to this spot, this quick?”

On a normal job, trucks would haul to any dozer. This project requires material to be moved from a specific location to a specific dozer in a color-coded zone in one of four project areas.

Archer Western hired Central Scales and Controls LLC, Denham Springs, La., to create tracking software. It was developed with Advanced Weighing System, Inc., Chippewa Falls, Wis., says John Sanders, Central’s owner. “AWS is a programming company that has a stock, automated system. Scale companies like us customize it to customer needs.”

Central installed five scales at LPV 109 and two at each of the borrow pits. Scales are fitted with readers that deliver data to the contractor from transponders fitted on haul trucks. Roughly 1,000 transponders are associated with the project, Sanders says. The cost for the system is divided among the contractor, pit owners and haulers. “One pit bought about 300 barcode transponders,” Sanders says.

The controls are “very tight,” Sanders says. Entering the pits, scales register the empty-truck, or “tare,” weight. After loading, each truck gets on the scale, and the computer makes a gross weight reading of truck plus material. When the truck arrives at the project, it rolls over another scale to make sure the gross weight reading matches. “That way the Corps and the contractor know it’s total product in there,” Sanders says.

The transponders daily transmit a date- and time-stamped reading to Archer Western. “All this is totally automatic, so there is no human error,” Sanders says.

By May 2011, the contractor expects to have completed the last lift. “Once it is built to that height, it has the ability to withstand a 100-year hurricane event,” Naomi says. “Once it gains strength, the factor of safety increases.”