Geomembrane barriers using integral fiber optics to monitor barrier integrity

• US 5,567,932 A
• Filed: 08/01/1995
• Issued: 10/22/1996
• Est. Priority Date: 08/01/1995
• Status: Expired due to Fees

• Current Assignee: Sandia Corporation (Martin Marietta Corporation)
• Original Assignee: Sandia Corporation (Martin Marietta Corporation)
• Inventors: Staller, George E., Wemple, Robert P.
• Primary Examiner(s): Westin, Edward P.
• Assistant Examiner(s): Lee, John R.
• Application Number:
  US08/509,850
• Time in Patent Office: 448 Days
• Field of Search: 250/227.14, 250/227.11, 250/227.15, 250/227.17, 250/227.18, 250/227.19, 250/227.27, 385/12, 385/13
• US Class Current: 250/227.14
• CPC Class Codes: G01M 3/38 by using light G01M3/02 takes precedence
• CPC Class Codes: G01V 8/10 Detecting, e.g. by using light barriers by reflection from the object G01S17/00

Abstract

This invention provides a geomembrane or geotextile with embedded optical sensors that are used to monitor the status of containment site barriers. Fiber optic strands are used to form the sensors that can detect and monitor conditions at the sites such as breaches, slope creep, subsidence, leachate levels, fires, and types of materials present or leaking from the site. The strands are integral to the membrane or textile materials. The geosythetic membrane is deployed at the site in a fashion similar to carpet laying. Edges of the membrane or textile are joined to form a liner and the ends of the membrane or textile become the connection zones for obtaining signals from the sensors. A connection interface with a control system to generate Optical Time Delay Response or other light signals for transmission to the optic fiber strands or sensors and also to receive reflected signals from the sensors is included in the system. Software to interpret the sensor signals can be used in the geosythetic monitoring system.

Claims

1. A barrier for a containment site, comprising:

containing means for restraining contents within a containment site, said containing means having a first surface for facing the contents of the containment site and an opposed second surface, said containing means comprising a geomembrane extending in a longitudinal direction; and

light transmission means for transmitting an optical signal, said light transmission means having a first end and a second end and being integral with said geomembrane, said light transmission means comprising a fiber optic strand having a tensile strength greater than or equal to the tensile strength of said geomembrane;

wherein a change in a received optical signal transmitted through said fiber optic strand is indicative of a change in said geomembrane.

2. A barrier as claimed in claim 1, wherein said transmission means is generally parallel to and between said first and second surfaces of said containing means in the longitudinal direction, said first end and said second end of said transmission means extending outward from said containing means.

3. A barrier as claimed in claim 2, wherein the first end of said transmission means is connected to an optical interface.

4. A barrier as claimed in claim 3, wherein a control system is connected to said optical interface, said control system generating an optical input signal, receiving a reflected optical output signal from said light transmission means, and analyzing the reflected signal to determine the status of said smart barrier.

5. A barrier as claimed in claim 2, wherein the second end of the light transmission means is connected to an optical interface.

6. A barrier as claimed in claim 1, wherein said transmission means is embedded within said containing means.

7. A barrier as claimed in claim 1, wherein the light transmission means is a plurality of fiber optic strands and each of said fiber optic strands runs generally parallel to each other and in the longitudinal direction of said containing means.

8. A barrier as claimed in claim 7, wherein said fiber optic strands transmit an input signal and a reflected output signal.

9. A barrier as claimed in claim 8, wherein the first end and the second end of each of said fiber optic strands extends in an outwardly direction from said containing means.

10. A barrier as claimed in claim 9, wherein each of said fiber optic strands run integral with the second surface of said containing means.

11. A barrier as claimed in claim 8, wherein the first end of each of said fiber optic strands is connected to an optical interface.

12. A barrier as claimed in claim 8, wherein the barrier is a composite barrier.

13. A barrier as claimed in claim 12, wherein the composite barrier includes a primary containing means and a secondary containing means, each having a first and a second surface, wherein a first surface of said secondary containing means is adjacent the contents of said containment site and a first surface of said primary containing means is in contact with an opposing second surface of said secondary containing means at an interface.

14. A barrier as claimed in claim 13, wherein the primary containing means includes at least one integral fiber optic strand extending in the longitudinal direction.

15. A barrier as claimed in claim 14, wherein said integral fiber optic strand is between the first and second surfaces of said primary containing means.

16. A barrier as claimed in claim 13, wherein the interface further includes at least one fiber optic strand.

17. A barrier as claimed in claim 14, wherein said secondary containing means further includes at least one fiber optic strand and said fiber optic strand is integrally within said secondary containing means.

18. A barrier as claimed in claim 17, wherein said fiber optic strand in said secondary containing means further includes an integral sensing means for detecting changing environmental conditions surrounding the fiber optic strands.

19. A barrier as claimed in claim 18, wherein said secondary containing means further includes engineered openings extending from the first surface to said sensing means.

20. A barrier as claimed in claim 13 wherein said primary and secondary containing means are a material chosen from the group consisting of:

a geomembrane and geotextile.