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  • 1.  Design of Small Earth fill Embankment Dam

    Posted 04-14-2018 02:02 PM
    Edited by Tirza Austin 04-14-2018 02:01 PM

    I have my final year project (undergraduate) in design assessment of an Earth fill dam. In which I will be doing modifications in the design of an existing Dam (Latambar Dam, Karak, Pakistan). If you have any idea about how to control seepage and increase the stability of Dam with cheaper material or any slope variations it would help me. Thanks...

    Shahid Ali S.M.ASCE

  • 2.  RE: Design of Small Earth fill Embankment Dam

    Posted 04-15-2018 01:52 PM
    Edited by Tirza Austin 04-15-2018 01:52 PM
    I've only done smaller dance nothing of the size but we use plastic membranes 30 mil to control seepage through the damn when we constructed it on the damn side, not the downwind side. It was very effective and we also try to use clay as a center material. Rock on the damn side also helps prevent erosion and damage to the membrane. 

    George Miles P.E., M.ASCE
    Alligator Engineering Inc
    New Smyrna Beach FL

  • 3.  RE: Design of Small Earth fill Embankment Dam

    Posted 04-16-2018 10:29 AM
    Edited by Tirza Austin 04-16-2018 10:28 AM
    The cross section you present is hopefully supported by borings and subsurface studies. 
    It is unclear what the material properties of you cross-section are....assuming that the upstream embankment material is somewhat  impermeable the length of the seepage path could likely be increased by laying a more impermeable layer on upstream toe for some distance upstream of the toe. Riprap added over a filter to downstream face and toe should add to stability... any such configuration changes should be supported by seepage checks and stability comps.

    Installation of a grout curtain could also be be considered to increase the seepage path.

    Jeffrey Franklin P.E., M.ASCE
    Civil Engineer
    Charleston WV

  • 4.  RE: Design of Small Earth fill Embankment Dam

    This message was posted by a user wishing to remain anonymous
    Posted 04-15-2018 01:53 PM
    Edited by Tirza Austin 04-16-2018 01:12 PM
    This post was removed

  • 5.  RE: Design of Small Earth fill Embankment Dam

    Posted 04-16-2018 10:29 AM
    There are several options available to control the seepage including core trench, positive cutoff, partial cutoff, slurry trench and upstream blanket etc. Seepage through the earth dams is the phenomenon which has potential to hamper the stability of the dam therefore you have no option but to provide the seepage control measures whether cheaper or not..

    Naimat Rasool S.M.ASCE

  • 6.  RE: Design of Small Earth fill Embankment Dam

    Posted 04-16-2018 10:29 AM
    You can also inject chemical grout, vertically into the soils, to stabilize and seal the dam. It may cost more but, will take a few days to install. Most poly-grouts have adhesive qualities and cure in 15 minutes. They behave like expanding soil epoxy. You can even pre-install soil nails to further stabilize the slopes.

    I hope this helps.

    Tony Alfano, ME
    Chair-Elect ASCE COPRI - North Jersey
    Regional Project Engineer
    Ground Works Solutions


  • 7.  RE: Design of Small Earth fill Embankment Dam

    Posted 04-16-2018 03:59 PM
    ​Certain kinds of clay material may be helpful in keeping the dam watertight - perhaps as a transitional layer between the bottom of the reservoir and up the internal face of the dam, despite the challenges of compaction and structural integrity for the dam structure. Maintaining water without infiltration can make this an effective strategy to maintain what water is captured.

    In the US, bentonite clay is often used for food and water contact as a liner, See Bentonite - Wikipedia  commonly utilized  by ranchers at the bottom of a depression to hold rainwater and create a drinking pond for cattle. 
    Another clay material, Zeolite, is often used here in the substrate of constructed wetlands to treat water that is meant to slowly be treated and return to groundwater, because it breaks down chemical molecules to make them more bioavailable when treating urban runoff that may contain contaminants.

    Lynne Baker A.M.ASCE
    HKA, San Diego CA

  • 8.  RE: Design of Small Earth fill Embankment Dam

    Posted 04-18-2018 02:37 PM
    Edited by Tirza Austin 04-18-2018 02:37 PM
    I don't have any more ideas but from what i understand, can't we use a different size of soil and compact it water tight along with impermeable membrane like plastic?

    I appreciate your suggestions. 
    Thank you

    Mansi Master S.M.ASCE
    Jersey City NJ

  • 9.  RE: Design of Small Earth fill Embankment Dam
    Best Answer

    Posted 04-19-2018 10:29 AM
    Edited by Shahid Ali 04-20-2018 06:22 AM
    It is not apparent from your post whether the majority of loss is through the embankment or due to the under-seepage.  Your dam seems to have both.  Assuming that the under-seepage is the key factor an apron or cutoff would seem appropriate.  The question you ask about low cost materials is obviously dependent on the locality and access to the materials.  The lowest cost option would likely be as suggested above to construct and apron on the upstream face and reservoir bottom to lengthen the seepage path, assuming that the substrate soils of moderate permeability.  To do this cost effectively, there must be a local source of natural low permeability clay.  If you have to import clay, or if the substrate consists of high permeability material, some sort of cutoff would likely be a better approach.  This could be done, as suggested above, by grouting, or you could construct a slurry trench.  This should be done upstream of the dam core for effectiveness and stability.  There are a number of other approaches, but all depend on variables that are not presented in your post.

    Michael Byle P.E., D.GE, F.ASCE
    Tetra Tech Inc.,
    Langhorne PA