2006-12-29 06:02:48 · 7 answers · asked by pam t 1 in Science & Mathematics ➔ Engineering
The short answer is that air under pressure is pumped in. Some water does get in, which is pumped out. The main thing is they dig out a tunnel a little at a time, shore up the surfaces, and and pump high pressure air in. This requires a period of depressurization for the workers, just like divers who go dowm deep. As an aside, the workers are called "Sand or Mud Hogs"
and the decompression disease is termed "Caissons Disease".
In divers it's called "the Bends".
Michael C.
2006-12-29 06:13:15 · answer #1 · answered by m_canoy2002 2 · 0⤊ 0⤋
There really isn't water around a tunnel. The tunnels are underground (OK, the ground is underwater). A trench is dredged out along the path of the tunnel. The tube sections are sealed at each end when they are sunken. They are joined together in the trench, and then the trench is refilled over top of the completed tunnel. And when all the tunnel sections are complete, the ends of the tube sections are cut through.
2006-12-29 15:18:45 · answer #2 · answered by H_A_V_0_C 5 · 0⤊ 0⤋
There are a number of methods of building a tube (technical name of a "tunnel" that goes underwater). The method you are asking about, "without getting water in it," is done by boring (with a giant drill) down into the bedrock. This is below all the silt and mud. Water does not permeate the bedrock because it is solid.
Because of fissures in the bedrock, there will be some water leaking in during the boring, but that water gets pumped out.
The other method of building a tube is to float sections of the tube on the water and then sink them. Underwater crews then join the sections together. Once all the sections are joined, the water is pumped out.
2006-12-29 19:45:14 · answer #3 · answered by Stan the Rocker 5 · 0⤊ 0⤋
It doesn't always happen. Some tunnels have pumps as part of their equipment. Most tunnels near water require pumping a great deal of water as they are built. Some tunnels use a form of concrete which seals them from water somewhat, but I think pumping is standard in most tunnels.
2006-12-29 14:38:44 · answer #4 · answered by Deirdre H 7 · 0⤊ 0⤋
Pump the water out as you're digging through the earth.
2006-12-29 17:07:21 · answer #5 · answered by Anonymous · 0⤊ 0⤋
there r 2 differnt ways. 1 is to seal the end and fill it with air pressure. 2nd is dig a sump[hole] in the floor and pump like crazy
2006-12-29 14:12:23 · answer #6 · answered by Anonymous · 0⤊ 0⤋
build it somewhere dry....
duh
2006-12-29 14:05:24 · answer #7 · answered by Anonymous · 0⤊ 1⤋