Originally posted by rygi23
Some don't that projects of the past we now know to be fact, no matter the scale, were done many years ago with basic means and that today's boring
and excavation technology available even 20 to 30 years ago far exceeds those capabilities.
I thought you would find this interesting...
A decade ago I saw, in person, a demonstration of "Jet Grouting" used to place cement pilings under a building that had been constructed many years
earlier and which had started to sink somewhat. It looked like a simple drilling rig but the machine was connected to a truck with a couple of tanks
and very loud pumps.
The drill holes were about 6 feet apart and the guy running the rig said that this means the underground cement columns will be close enough to touch
each other and form a "wall" around the entire perimeter of the building.
Ever since I saw that demonstration, I realized we have the technology to build underground bunkers in very soft soils without doing any excavation
first. To do this, all you need to do is make an artificial underground "cave" out of cement. You build a cement wall about 10 feet high around the
entire perimeter and then you build a cement "cap" over the entire thing.
Once that is done, you can "excavate" the soft soil using high pressure water and pumps which is the same equipment you used for the jet grouting in
the first place. You would end up with a slurry that could easily be pumped into nearby rivers.
So keep an eye out for drilling rigs spending a lot of time at that site. Most drilling is done for very short periods (like a day or two) but for
jet grouting the rigs will be working there for weeks.
Jon
[edit on 8.31.2009 by Voxel]