Abstract
This paper describes the new austrian tunneling method (natm) tunnel waterproofing system using geosynthetics. The advantages of using a nonwoven geotextile and a plastic geomembrane sheet material for the primary drainage and waterproofing are summarized. The method of installing and inspecting the geosynthetics is described and illustrated with photographs. Example material specifications for both polyvinyl chloride and high-density polyethylene are presented based on washington metropolitan area transit authority (wmata) tunnel specifications. This paper appears in transportation research record no. 1248, Geosynthetics, geomembranes, and silt curtains in transportation facilities.