Cutoff: Difference between revisions
Rmanwaring (talk | contribs) (Created page with "<!-- Delete any sections that are not necessary to your topic. Add pictures/sections as needed --> __NOTOC__ ---- {{Picture <!-- Add image file name (ex.image.jpg) --> |image= CutoffWallConstruction.jpg <!--Add link if applicable --> |link= <!-- Add picture caption --> |caption= Cutoff wall construction along the American River }} <!-- Introductory paragraph or topic page summary --> "Various methods of seepage and percolation control can be used, depending on...") |
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[[Category:Underseepage]] | |||
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|caption= Cutoff wall construction along the American River | |caption= Cutoff wall construction along the American River. | ||
(Image Source: [http://www.publicdomainfiles.com/show_file.php?id=14003189411605 USACE]) | |||
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" | "Seepage barriers, or cutoff walls, can be an effective means for controlling seepage through an earthfill dam or its foundation. Since approximately the early 1970s, the various types of cutoff walls available to embankment designers have increased with advances in [[construction]] methodologies and technology. The industry has made significant improvements in the equipment used to construct cutoff walls and in the efficiency of their [[operation]]. Increasingly, cutoff walls are being considered as a primary modification component within existing earthfill embankments that have a history of chronic seepage related problems or that undergo an acute seepage incident. With the wide array of cutoff wall alternatives, they can be the technically preferred and most cost-efficient methods to remediate an identified seepage problem given the difficulties of creating an earthfill cutoff within an existing embankment with an active reservoir."<ref name="DS13-16">[[Design Standards No. 13: Embankment Dams (Ch. 16: Cutoff Walls) | Design Standards No. 13: Embankment Dams (Ch. 16: Cutoff Walls), USBR, 2014]]</ref> | ||
"Various methods of seepage and percolation control can be used, depending on the requirements for preventing uneconomical loss of water and the nature of the foundation in regard to [[stability]] from seepage forces. Cutoff trenches, sheet piling, mixed-in-place concrete pile curtains, slurry trenches, [[grouting]] of alluvium, or combinations of these methods have been used to reduce the flow and to control seepage forces. Blankets of impervious material, extending upstream from the toe of the dam and possibly covering all or part of the abutments, are frequently used for the same purpose."<ref name="SmallDams">[[Design of Small Dams | Design of Small Dams, USBR, 1987]]</ref> | |||
==[[ | "Construction of conventional rolled earthfill cutoff trenches, whether in a new earthfill dam or as a component to the modification of an existing dam, can be a prohibitively expensive operation, depending on the required depth, the existing natural [[groundwater]] conditions, and the availability of suitable impervious material. Cutoff walls can be a viable alternative for reducing seepage through [[Embankment Dams|embankment dams]] and their foundations. Cutoff walls can be constructed by a variety of methods that do not require foundation [[dewatering]] and that greatly reduce the amount of excavation from that required for a rolled earthfill cutoff. Another advantage to cutoff walls is that they can often be constructed in very limited working spaces."<ref name="DS13-16"/> | ||
==<noautolinks>Best Practices Resources</noautolinks>== | |||
{{Document Icon}} [[Design Standards No. 13: Embankment Dams (Ch. 16: Cutoff Walls) | Design Standards No. 13: Embankment Dams (Ch. 16: Cutoff Walls), USBR]] | |||
{{Document Icon}} [[Design of Small Dams | Design of Small Dams, USBR]] | |||
==<noautolinks>Trainings</noautolinks>== | |||
{{Video Icon}} [[On-Demand Webinar: Foundation Cutoff Walls for Dams and Levees]] | {{Video Icon}} [[On-Demand Webinar: Foundation Cutoff Walls for Dams and Levees]] | ||
{{Video Icon}} [[On-Demand Webinar: Seepage Rehabilitation for Embankment Dams]] | {{Video Icon}} [[On-Demand Webinar: Seepage Rehabilitation for Embankment Dams]] | ||
Latest revision as of 15:59, 18 July 2023
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| Cutoff wall construction along the American River.
(Image Source: USACE) |
"Seepage barriers, or cutoff walls, can be an effective means for controlling seepage through an earthfill dam or its foundation. Since approximately the early 1970s, the various types of cutoff walls available to embankment designers have increased with advances in construction methodologies and technology. The industry has made significant improvements in the equipment used to construct cutoff walls and in the efficiency of their operation. Increasingly, cutoff walls are being considered as a primary modification component within existing earthfill embankments that have a history of chronic seepage related problems or that undergo an acute seepage incident. With the wide array of cutoff wall alternatives, they can be the technically preferred and most cost-efficient methods to remediate an identified seepage problem given the difficulties of creating an earthfill cutoff within an existing embankment with an active reservoir."[1]
"Various methods of seepage and percolation control can be used, depending on the requirements for preventing uneconomical loss of water and the nature of the foundation in regard to stability from seepage forces. Cutoff trenches, sheet piling, mixed-in-place concrete pile curtains, slurry trenches, grouting of alluvium, or combinations of these methods have been used to reduce the flow and to control seepage forces. Blankets of impervious material, extending upstream from the toe of the dam and possibly covering all or part of the abutments, are frequently used for the same purpose."[2]
"Construction of conventional rolled earthfill cutoff trenches, whether in a new earthfill dam or as a component to the modification of an existing dam, can be a prohibitively expensive operation, depending on the required depth, the existing natural groundwater conditions, and the availability of suitable impervious material. Cutoff walls can be a viable alternative for reducing seepage through embankment dams and their foundations. Cutoff walls can be constructed by a variety of methods that do not require foundation dewatering and that greatly reduce the amount of excavation from that required for a rolled earthfill cutoff. Another advantage to cutoff walls is that they can often be constructed in very limited working spaces."[1]
Best Practices Resources
Design Standards No. 13: Embankment Dams (Ch. 16: Cutoff Walls), USBR
Trainings
On-Demand Webinar: Foundation Cutoff Walls for Dams and Levees
On-Demand Webinar: Seepage Rehabilitation for Embankment Dams
Citations:
Revision ID: 7269
Revision Date: 07/18/2023