China Yangtze Three Gorges Dam
completely blocked on Nov. 6,
2002 at the Three Gorges when
the opening in the diversion canal
of the Dam Project was closed.
Hence the natural flow of the
mighty river at the Three Gorges
At the location of the Sandouping
dam site, the river valley is
relatively open and broad, with a
small islet known as Zhoubaodao in the river, which is favorable for a river
diversion scheme with phased construction. As regards communications,
there is a railway to Yichang and a waterway to the dam site. A 26 km-long
expressway has also been constructed from Yichang to the dam site. The
bedrock at the dam site is sound, intact granite with a compressive strength of
100 developed. The rock mass has only very slight permeability.
Layout of Three Gorges Dam
The Three Gorges Project is designed with a concrete gravity dam with a
crest elevation of 185 meters and maximum height of 175 meters. The dam
axis runs 2, 309. 47 meters long, which is even longer than the noted Grand
Coulee Dam of US.
The 483-meter spillway, located in the middle
of the main dam, has 23 bottom outlets
dimensioned at 79 meters. Each of its 22
surface sluice gates measures 8 meters wide.
The maximum discharge capacity of the TGP
is 116,000 cubic meters, the biggest in the
Two powerhouses, flanking the spillway, accommodate altogether 26 sets of
turbine-generators. As the world's biggest unit ever made, each has a
generating capacity of 700MW. The 643.6-meter-long left powerhouse, 60
meters longer than the 584.2-meter-long right one, houses 14 sets of
generators. With all these huge generators, the TGP is designed to generate
electricity of 84.7 TW/h.
On the right bank, enough room has been preserved for the future
underground powerhouse of 6 turbine generator units with 4, 200 MW of
installed capacity. The intakes of these units will be constructed
simultaneously with the project.