Good morning alan, yes I agree it could be bored using a steering head for direction,but IMO don't believe it would be necessary. There are actually two river crossings to contend with, the Nile,being the 630 meters wide by 4.3 meters maximum depth. , and the Atbara river which is nearly dry (statements apply during the dry season).
As I recall, there was special consideration for any irrigated land
along the route and it is to be avoided (except at the Nile crossing).
As you know, boring work can be very destructive to each side of the bore ( after digging bore pits and driving sheet piling etc.) combined with the fact that concrete and good aggregate are at a premium, for these reasons, IMO boring would be avoided if possible.
But, you certainly could be right,I don't know for sure one way or the other. I do know that a 2000'+/- directional bore is a helluva project.
One other note,the selected route parallels existing road and rail infrastructure along much of the route,I keep wondering where the trains cross the river and if the line could be piggybacked on a tressel.. I guess we'll find out eventually,great discussion ,I'm enjoying it...DD
PS: without a question,direction boring is neat stuff,worked on a project where we had to bore under Bypass 17 in Mrytle Bch.,54" casing. Note: when we preasure tested the 36" line @ 150 psi(water),
we blew a 10,000lb shutoff value out of the ground and over 4 lanes of traffic on the divided highway.yahoo<vbg> |
