When is the use of a geotextile under/overlayment appropriate?
As touched on earlier, use of a geotextile underlayment (under the liner) with the PPL-24 is rare (see Question 2). It is always a judgment call, but we don’t require the underlayment unless it is impossible or impractical (cost ineffective) to get an acceptable subgrade any other way. The “other way” is usually to haul in and spread clean fill over the entire area to be lined. Often it is cheaper and faster to spread an underlayment over angular rock subgrades than the “other way”. Use of the geotextile as an overlayment (over the liner) is normally for having a separation between the liner and any type of fill, rock, gravel, rip-rap, etc. that is to be placed on top of the liner for various reasons. As an option, we often sell a “ribbon” of geotextile overlayment (typically 8oz. per square yard non-woven needle-punched polypropylene, whew!) usually simply referred to as “geo”, which is installed over the liner on the upper perimeter and keyed into the anchor trench or shelf right alo
Related Questions
- Could you provide examples of "significant" and "minor" deficiencies and suggest appropriate methods for reporting them in the Institutional Semiannual and Annual Reports?
- What is the appropriate attire for the Opening Session and Awards Ceremony?
- When is the use of a geotextile under/overlayment appropriate?
