A question if you please.
It would appear that the upper portion of the spill way is compromised, most likely fatally, but the DWR is pretty much stuck with it for the foreseeable future.
I have seen on highway overpasses here in KC where the DOT has placed an epoxy coating on the roadway. This coating has been in place for at least 5 years and seems to be holding up rather well. I would guess that this process could be done rather quickly and given the massive amounts of money already spent fairly cheaply:-)
In your opinion do you think this would work as a sealant to stop/reduce water infiltration through the spill way?
Regards
alfa6 ;>}
High Tech materials are available such as super-low-viscosity (SLV) epoxy for "micro crack healer-sealer" including expandable chemical urethane to stop multiple leak branching sources. These materials have been used exactly for modern dam spillway repairs by reputable & experienced concrete specialization companies.
Oroville's spillway design poses many challenges*. They don't even know why the waterflow continues to discharge for a while after the gates are closed. It's clear that the original construction placed a layer of washable material -such as compacted aggregate & now revealed "clay" in spots - between the bedrock (or less than bedrock) and the slabs. Voiding formed and now there is discussion of "channel flows" (or "piping" in the engineering term) nearly everywhere (to some degree). Look at the "void seam" before they shotcreted the damaged upper spillway.
There is evidence that the "voiding" combined with the "thinning" of the slabs by the drain piping design is causing a flexure of the slabs** when the spillway is used (at a decent flow). This could cause all of the patching at the cracked drain profiles to re-crack.
So the question becomes: (IF the MS needs a superior sealing state to reduce problematic developments) - What are the "flexing" dynamics of the spillway? This will drive the answer to the effectiveness of a technological materials application choice.
btw- there are some amazing epoxies available today. One type that I favor is an aerospace grade epoxy that is used to bond joints in high stress flexing and aircraft grade reliability performance requirements in copter blades. It is expensive & is made by 3M.
*Drains emplaced "upward into the slabs" severely "thinned" the concrete slabs. The slabs severely cracked above nearly every single drain line run on the entire spillway. The 50 yr old spillway design does not have seam "water stops". The spillway concrete pour was emplaced upon a washable compacted gravel bed. Thus large crack volume + seams area per slab drives a pressurized waterflow from spillway operation.
**More flexure means continued failure of concrete surface patching, leading to re-cracking of the patch in addition to surface stresses exposing the seams to spontaneous spalling ("chipping").
I’m far from being an expert in such things, but I think that it’s possible that something of that nature could be used. One of the things that has to occur is that the individual slabs of concrete have to be able to slide in a way that allows contraction/expansion of the concrete based on heating and cooling (not to mention the varying weight of water depending on the amount of spilling taking place). The joints allow this, but might also be allowing some leakage as a result.
I’m not sure that a perfect seal is desired, though, unless the sealing material had enough flexibility to allow for some movement. So maybe perfect isn’t quite the goal, but reduction of leakage and a close eye on outflows through the side drains is more in order.
So there’s my non-answer/musings. :)
The spillway upper section just has to last until mid June. If they can get another 80 days out of it until Spring melt and rains are peaked then they can replace the whole dam thing. (That was a bad pun wasn’t it? — blame the Jayhawks)
I don’t think they want new chem coatings in the feather or to spend money for momentary band aids.
The spillway upper section just has to last until mid June. If they can get another 80 days out of it until Spring melt and rains are peaked then they can replace the whole dam thing. (That was a bad pun wasn’t it? — blame the Jayhawks)
I don’t think they want new chem coatings in the feather or to spend money for momentary band aids.