geotextile

noun

1. Any strong, permeable fabric used in earthworks for any of a number of purposes, including separation of soil layers, filtering, reinforcing, erosion protection and protection of drainage pipes from clogging.

   “You need to excavate and remove the topsoil, line the subsoil with a geotextile, then lay and compact hardcore.”

   “The design also included geotextile lining of the trench in which the drainage pipe was buried.”