tunnels under the Three gorges dam? There’s a whole bunch of imprecise rambling about possible tunnels under the thing. The notion that the chicoms actually dug a tunnel(s) in the bed rock that the dam sets on is beyond fanciful. After they cleared the dirtish/gravelish overburden they did indeed drill and take core samples of the underlying rock.
But the structure itself would have to have passages, access tunnels, drainage paths of a wide variety to make maintainence of the internal working parts possible. To one degree or another the dam would leak, at least in little bits here and there. Remember the thing is 600 feet high so the water pressure at the base is at least 250 psi. That’s a lot for concrete to contain.
Simultaneously, with large, thick, deep, concrete structures it’s necessary to build in water pipes, which double as re-bar re- enforcement, to cool the large concrete sections. Those cooling pipes need to last for half a century since it takes at least that long for the concrete to mature.
As I recall it wasn’t until the mid 1980’s that they shut down the cooling system in Hoover dam which had been built half a century earlier.
Bottom line: yeah there are spaces inside the dam but no one is in there doing sneaky stuff. They’re working their buttz off to keep it operating. It’s a hydro dam so they need to get some power out of it.
Good points, OWB - I had the opportunity to take an in-depth training tour of TVA’s Chickamauga Dam near Chattanooga a couple of years ago. There are many hallway/passages down pretty deep below where the water level is, even on the low side of the dam. Access for inspection, running wiring and piping, maintenance, etc. It’s imperative that you get access to a lot of parts of the structure to keep tabs on it and make repairs as necessary.
Interesting factoid - concrete in dams swells over time. And creates great pressures in the structure. It was necessary, after several years, to take concrete saws and cut slices into the thick concrete to relieve pressure at the Chickamauga dam and others along the Tennessee River and elsewhere. There’s some science (real science, not political science) behind it, but the narrow cuts into the concrete, along with proper grouting, served to prolong the life of many dams, and prevent the concrete from cracking under its own pressure.
Another fact - no dam is perfectly leak proof. In the lowest bowels of the Chickamauga dam, in one of the lower walkways, there is a trough cut along the side of the walkway with water freely flowing in it. It is constantly pumped out into the river.
By the way, Three Gorges Dam is massive, and dwarfs most dams in the world.
***Bottom line: yeah there are spaces inside the dam but no one is in there doing sneaky stuff. They’re working their buttz off to keep it operating. It’s a hydro dam so they need to get some power out of it.
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Agreed, OWB.
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