Monitoring Transport Network Infrastructure

• US 20150013465A1
• Filed: 02/22/2013
• Published: 01/15/2015
• Est. Priority Date: 02/24/2012
• Status: Active Grant

• Current Assignee: Optasense Holdings Limited (Luna Innovations, Inc.)
• Original Assignee: Optasense Holdings Limited (Luna Innovations, Inc.)
• Inventors: Godfrey, Alastair
• Granted Patent: US 9,561,812 B2
• Time in Patent Office: Days
• US Class Current: 73/655
• CPC Class Codes: B61L 1/166 Optical
• CPC Class Codes: B61L 23/04 for monitoring the mechanical state of the route
• CPC Class Codes: B61L 23/044 Broken rails
• CPC Class Codes: B61L 23/045 Rail wear
• CPC Class Codes: B61L 23/047 Track or rail movements
• CPC Class Codes: B61L 23/048 Road bed changes, e.g. road bed erosion
• CPC Class Codes: B61L 27/53 for trackside elements or systems, e.g. trackside supervision of trackside control system conditions
• CPC Class Codes: G01M 5/0025 of elongated objects, e.g. pipes, masts, towers or railways G01M5/0058 takes precedence
• CPC Class Codes: G01M 5/0033 by determining damage, crack or wear
• CPC Class Codes: G01M 5/0066 by exciting or detecting vibration or acceleration vibration testing of structures G01M7/00
• CPC Class Codes: G01M 5/0091 by using electromagnetic excitation or detection
• CPC Class Codes: G01N 29/04 Analysing solids using acoustic emission techniques G01N29/14

Abstract

This application relates to conditions monitoring of structures forming part of a transport network, e.g. structural health monitoring of structures, especially tunnels. The method involves performing distributed acoustic sensing (DAS) on at least one optical fibre (104) deployed so as to monitor the structure (206). The acoustic response to movement of traffic (205) on the network in the vicinity of the structure is detected and analysed to detect the acoustic response (303, 304) of the structure. The acoustic response of the structure is then analysed to detect any change in condition. The method thus uses the normal movement of traffic on the network, e.g. trains on a rail network, to acoustic excite the structure and detects the resultant response. The method is particularly useful for condition monitoring of tunnels on a rail network.

Claims

1. A method of condition monitoring of a structure forming part of a transport network comprising:

performing distributed acoustic sensing on one or more optical fibres deployed to monitor said structure to provide a measurement signal from each of a plurality of acoustic sensing portions;

analysing the measurement signals generated from movement of traffic on the transport network in the vicinity of said structure to identify acoustic signals associated with said structure; and

analysing said acoustic signals associated with said structure to provide an indication of any changes in condition of said structure.

2. A method as claimed in claim 1 wherein analysing said acoustic signals associated with said structure comprises comparing the acoustic signals with previously acquired acoustic signals.

3. A method as claimed in claim 1 wherein analysing said acoustic signals associated with said structure comprises identifying acoustic waves propagating in the structure.

4. A method as claimed in claim 3 comprising identifying any discontinuities in acoustic waves propagating in the structure.

5. A method as claimed in claim 3 wherein analysing said acoustic signals associated with said structure comprises analysing the propagation speeds of acoustic waves in the structure.

6. A method as claimed in claim 5 comprising identifying acoustic waves propagating at different speeds in the structure.

7. A method as claimed in claim 1 wherein the acoustic signals associated with said structure are those detected by the sensing portions before and/or after the traffic movement past the relevant sensing portion.

8. A method as claimed in claim 1 wherein the acoustic signals associated with said structure comprise a low frequency response.

9. A method as claimed in claim 1 further comprising performing distributed acoustic sensing on said one or more optical fibres to track the movement of traffic on the transport network.

10. A method as claimed in claim 9 wherein at least part of said one or more optical fibres is deployed along the path of the transport network.

11. A method as claimed in claim 10 wherein a first optical fibre of said one or more optical fibres has at least a first section deployed along the path of the transport network and at least a second section deployed to monitor said structure.

12. A method as claimed in claim 11 wherein the second section of fibre is attached to the structure.

13. A method as claimed in claim 1 wherein the transport network is a rail network.

14. A method as claimed in claim 13 wherein said structure comprises a tunnel.

15. A method as claimed in claim 14 wherein said one or more optical fibres comprises at least one optical fibre deployed alongside a rail track running through the tunnel.

16. A method as claimed in claim 13 wherein said structure comprises the rail track.

17. A method of condition monitoring of structures forming part of a transport network, the method comprising:

receiving a plurality of measurement signals acquired by a one or more distributed acoustic sensors having one or more optical fibres deployed to monitor said structure;

analysing the measurement signals generated from movement of traffic on the transport network in the vicinity of said structure to identify acoustic signals associated with said structure; and

analysing said acoustic signals associated with said structure to provide an indication of any changes in condition of said structure.

18. (canceled)

19. A distributed acoustic sensing system comprising:

an interrogator unit for, in use, performing distributed acoustic sensing on one or more optical fibres deployed to monitor a structure of a transport network to provide a measurement signal from each of a plurality of acoustic sensing portions; and

a processor configured;

to analyse the measurement signals generated from movement of traffic on the transport network in the vicinity of said structure to identify acoustic signals associated with said structure; and

analyse said acoustic signals associated with said structure to provide an indication of any changes in condition of said structure.

20. A distributed acoustic sensing system according to claim 19 comprising at least one optical fibre deployed to monitor the structure.

21. A distributed acoustic sensing system according to claim 20 wherein and at least part of an optical fibre is deployed along the path of a transport network.

22. A distributed acoustic sensing system according to claim 21 wherein the transport network is a rail network.

23. A distributed acoustic sensing system according to claim 22 wherein the system is configured to monitor the condition of one or more tunnels on the network.

24. (canceled)