1) The virtual anchor length is a distance. This distance represents the length of pipe (from some reference point) that is needed to build up enough friction resistance to restrain the thermal growth. Points past the virtual anchor length have no effect on piping on the "near side" of the reference point.

2) The virtual anchor length is a fictitious point, you can't walk up to it. For example, assume you're standing next to a location where the pipe is buried, and the VA is 94.5 M down the line. If you walk down the line 50 M, the VA is still 94.5 M away, not 44.5 M. Why - because you moved the reference point.

The VA is useful in that it is an indicator of where you can stop modeling the pipe system. For example, assume your pipe leaves the area of interest and runs for several kilometers. If your VA from the last point of interest is 100M, then you can stop modeling at any point after that 100M - you don't need to model several kilometers of pipe.

3) No, the virtual anchor point doesn't exist, it is not real. The VA is just a distance past which you aren't concerned with (compared to your area of interest).