Quote:
Originally Posted by cjones2451
Passed a line up of 5 dump trucks there this morning  |
The softer the soil, the faster the TBM can advance in any 24 hour period. Hence, more spoil, and more trucks to cart it away.
So, the softer the soil the better, from one point of view.
But you have a potential problem here, if the soil is too soft (meaning not bound together - such as a sand lens), then the cutter head is swamped with material falling into the void created by the TBM. This creates a void above the cutting area, which leads to displacement on the surface if there is no intervening firmer layer above it all that can support itself.
So the current rate of spoil generation (and there is a lot, I have been watching the pics) is great from an advance rate point of view.
They are cutting soft material and moving fast. Let us all hope that the material stays "just right" ... meaning not too soft (no voids) and not too hard (fast advance).
None of us want another stumble into material that is too soft and void prone ... or we will get yet another 7 month delay for "planned maintenance".
Threaded Mode