Anybody know what this is? I presume it's a perennial weed of some sort
as it keeps popping up again.

http://www.dentonmiller.net/Site/Stu...6/4_WEEDS.html

Right now, I'm trying to build a raised bed from railway sleepers, and
the area that will be enclosed is full of this stuff, so I want to know
the best way to deal with it.....should I glyphosate it then pull it
all out and just chuck new topsoil over the top, or is it something
that needs to be dug out first?