Slurry Wall History - Essay Example

Slurry Wall Introduction Slurry walls also referred to as continuous diaphragms are structures made and case in slurry trenches. The trench excavation is originally supported by either polymer or bentonite-based slurries that are used in preventing soil incursions in the dug trench (Ryan & Day, 2002). Diaphragm walls denote the last condition after the slurry is replaced by trimmed concrete, which plays the role of a structural system either as part of a long-lasting structure or impermanent excavation support.

Slurry walls were also used as flow barriers primarily in waste containment (Evans, Prince, & Adams, 1997). They provided a low permeability obstacle to contaminant transport. Slurry Wall HistoryThe first slurry wall was built in Italy. Icos built the wall in Italy by using bentonite slurry support as the cut-off wall. He went on to construct the first slurry wall for the Milan Metro. In the mid-1960s, European contractors introduced slurry walls in the United States. It was first used in the World Trade Center found in New York, the Bank of California found in San Francisco, and the CAN building found in Chicago.

Many projects of the slurry wall in the United States are found in Chicago, San Francisco, Washington, New York, and Boston. Slurry walls are used extensively in the Central Artery/Tunnel project. This project involved many covers and cut tunnels built under the prevailing artery. Slurry Wall EquipmentThe technology behind the slurry wall centers on specific equipment used to excavate slurry trenches. The mechanical clamshell is the simplest kind of trenching equipment and is put on a Kelly bar. Different contractors have developed particular equipment such as hydro mills, hydraulic clamshells, or fraise (Mulligan, Yong & Gibbs, 2001).

Slurry Wall ApplicationsThese walls are used in retaining the foundations of the wall and retaining control of the wall water. Additionally, they are used as long-lasting basement walls in top-down construction methods and used as earth retention walls for tunnels, excavations, and basements. They are also used in vertical foundation elements with high capacity (Opdyke & Evans, 2005). Diaphragm walls for cut-off wall applications are used as cut-off curtains, gas barriers in areas with landfills, seepage control, and contaminated groundwater.

Moreover, the diaphragms are used in seepage and water control for deep excavations. Costs of slurry wallsThe construction cost of the slurry wall for cut-off barriers is much cheaper than the construction of a diaphragm wall for deep excavations. The alterations arise mostly from the differences in the construction methods. In diaphragm walls, the perimeter of the wall is made panel by panel. Also, reinforcement cages are practically always used. In cut-off walls, constructing the wall is quick as the excavation of a continuous trench is done, and backfilled and reinforcement cages are not used frequently (Evans, Prince, & Adams, 1997).

Slurry wall limitationsConstruction of the slurry wall needs heavy construction equipment to be used. This equipment needs a reasonable site area, significant mobilization costs, and headroom. In a situation of inadequate headroom conditions, small cranes can be used and the procedure can be changed to remote backfill mixing. Remote backfill mixing is where the dug soil is conveyed and mixed to a secluded location and returned later as a backfill. An individual needs to check that soil bentonite and bentonite slurry used have the ability to withstand chemical attacks from the insitu soils (Ryan & Day, 2002).