Vertical Bore Hole in Earth Dam
Vertical Bore Hole in Earth Dam
(OP)
Does anyone have an opinion on drilling bore holes in shorter (less than 40 feet tall) earth dams? I have been told to avoid this practice at all costs as a hole in a dam is not a good thing! I suppose drilling in a clay core is one issue but a vertical small diameter hole drilled off the crest properly (tamped) backfilled should not be an issue. Getting past that, if holes are drilled, is there a preferred backfill method or material to use? Thanks for any input.





RE: Vertical Bore Hole in Earth Dam
As the dam height increases or the dam material is soft, you run the risk of hydrofracturing the dam. This can cause cracks to form and create problems, however, for a 40 foot dam I would generally not expect a problem.
The vertical hole is not really a problem. Most larger dams have many, their called peizometers.
RE: Vertical Bore Hole in Earth Dam
RE: Vertical Bore Hole in Earth Dam
I haven't checked myself, but you could look through USACE and USBR publications on the web relating to dams.
Just a thought.
Jeff
Jeffrey T. Donville, PE
TTL Associates, Inc.
www.ttlassoc.com
RE: Vertical Bore Hole in Earth Dam
Some people like hollow-stem flight augers. Some COE districts have lately been very interested in sonic drilling.
Gotta ask yourself how important the hole is. How thick is the core and what's it made of - how easily could you fracture it? What's on each side of the core - what are the consequences of fracturing it? Is there a core? Finally, as Dirty Harry said, "You gotta ask yourself, do you feel lucky?"
A hole has to be VERY important to be drilled through embankment core, especially if the core is thin.