Is the fabric similar to tyvek house wrap?
No the fabric is porous and is made of something incredibly tough, maybe something like kevlar. It's kind of like that stuff you put down under mulch to keep the weeds from growing through, only much tougher. The water will drain through it but the stone can't cut it, so it prevents the stone from being pushed down into the dirt and disappearing. They also make a version that's very heavy for use under highways, but that stuff is about 1/4" thick and expensive.