CN211504169U - Water seepage blind ditch damage detection system based on distributed optical fibers - Google Patents
Water seepage blind ditch damage detection system based on distributed optical fibers Download PDFInfo
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- CN211504169U CN211504169U CN202020500379.3U CN202020500379U CN211504169U CN 211504169 U CN211504169 U CN 211504169U CN 202020500379 U CN202020500379 U CN 202020500379U CN 211504169 U CN211504169 U CN 211504169U
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Abstract
The utility model relates to an underground drainage field, especially a infiltration french drain damage detecting system based on distributed optical fiber, wherein detecting system includes distributed detection optic fibre and optical time domain detector, distributed detection optic fibre sets up in french drain collector pipe outer wall along the axial, distributed detection optic fibre includes many detection optic fibre and a plurality of optical fiber splice, many it passes through to detect optic fibre the optical fiber splice is established ties, optical time domain detector to distributed detection optic fibre emission light detects the signal, and the receipt is followed the distributed detects the light signal that optic fibre returned. The utility model discloses a to detect optic fibre setting on the french drain collector pipe, can fix a position the damaged position of infiltration french drain fast through the optical time domain detector, for the maintenance provides the guide, avoid the construction of large tracts of land to look for damaged point, the effectual construction cost that has reduced has improved the efficiency of construction.
Description
Technical Field
The utility model relates to an underground drainage field, especially a infiltration french drain damage detecting system based on distributed optical fiber.
Background
The blind ditch is used as an underground drainage facility for draining underground water and reducing underground water level, and is widely applied to drainage of railway and highway subgrades. The traditional blind ditch widely adopted at present is filled with coarse-grained materials such as crushed stones and gravels and is provided with a permeable pipe in a roadbed or a foundation. The blind ditch is easy to crack and damage due to the influence of upper load, base expansion force, uneven settlement of a foundation and the like in the using process to form a water leakage point, so that the drainage efficiency of the blind ditch is reduced on one hand, and on the other hand, the underground water leaked from the damaged point is easy to deteriorate peripheral soil bodies to form diseases. The blind ditch belongs to secret hidden engineering, in case take place the damaged back, is difficult to confirm damaged position and damaged degree, needs large tracts of land excavation in order to look for the spot of leaking water when maintaining, and the engineering volume is big, and influences existing railway, highway operation.
The invention patent of application No. 201810969044.3 discloses an OFDR (Optical frequency domain Reflectometer) distributed Optical fiber based online monitoring system and method for drainage pipelines, which is based on OFDR technology, and a plurality of Optical fiber monitoring groups are arranged at different filling degree positions in the drainage pipeline, so that local breakage and damage of the drainage pipeline can be monitored, but the system still has limitations: (1) the optical fiber is adhered to the inner wall of the drainage pipeline by epoxy resin, and a single water collecting pipe of the water seepage blind ditch is usually longer than 6m, has the diameter of 30-40cm and has narrow internal space, so that the optical fiber cannot enter the adhered optical fiber; (2) a plurality of optical fiber detection groups are needed, temperature optical fibers and strain optical fibers are involved, and the system is complex; (3) although the OFDR technology has high measurement sensitivity and spatial resolution, the measurement distance is short (the maximum detection length is about 100m), a large amount of signal noise exists, the measurement result is difficult to analyze, and the OFDR technology is not suitable for actual geotechnical engineering.
SUMMERY OF THE UTILITY MODEL
The utility model aims to provide a: aiming at the problem that the water seepage blind ditch can not quickly locate the damaged position, a water seepage blind ditch damage detection system and method based on distributed optical fibers are provided.
In order to realize the purpose, the utility model discloses a technical scheme be:
a water seepage blind ditch damage detection system based on a distributed optical fiber comprises a distributed detection optical fiber and an optical time domain detector,
distributed detection optic fibre sets up in the french drain collector pipe outer wall along the axial, distributed detection optic fibre includes many detection optic fibre and a plurality of optical fiber splice, many detection optic fibre both ends all are provided with optical fiber splice, adjacent two detection optic fibre passes through at the french drain sump pit the optical fiber splice is established ties, the optical time domain detector passes through optical fiber splice with detection optic fibre is connected, forms the detection return circuit, the optical time domain detector to distributed detection optic fibre emission light detection signal receives the follow the light signal that distributed detection optic fibre returned.
The optical time-domain reflectometer adopts an OTDR (optical time-domain reflectometer) technology, has the functions of emitting detection light pulses and receiving backward Rayleigh scattering and reflected light signals, and can convert the received light signals into a backward scattering light power curve. When the seepage blind ditch is slightly deformed or damaged to cause the micro-bending of the detection optical fiber, the light intensity of the backward Rayleigh scattering light at the position is greatly attenuated; when the detection optical fiber is broken due to large deformation of the water seepage blind ditch, end face reflection occurs at the position; the position and damage degree of defects and disturbance can be determined by measuring the time of arrival and power loss of the back scattering light, the OTDR signal noise is smaller than the OFDR, and the optical time domain reflectometer is connected with the detection optical fiber only during detection and does not need to be placed on a detection site for a long time.
A infiltration french drain damage detecting system based on distributed optical fiber, through adopting distributed optical fiber, arrange many detection optic fibre respectively on the french drain collector pipe, detection optic fibre between the adjacent french drain sump pit can constitute a detecting element, adjacent detecting element's detection optic fibre accessible optical fiber splice connection, form longer detection loop, after single detecting element is impaired, can not influence other detecting element's function, single detecting element damages the back, detection device can be connected with the damage unit both ends respectively and come the damaged position of definite detection french drain, need not use complicated optical fiber detection group, moreover, the steam generator is simple in structure, and low cost.
The utility model discloses directly set up distributed detection optic fibre at the french drain collector pipe outer wall, solved the difficult problem of optic fibre installation, the installation of the optic fibre of being convenient for.
Preferably, the optical time domain detector is disposed at a start end of the distributed detection optical fiber, and transmits an optical detection signal to a tail end of the distributed detection optical fiber and receives an optical signal returned by the distributed detection optical fiber.
Preferably, the optical fiber connector is arranged at the blind ditch water collecting well, so that constructors can find the detection optical fiber quickly.
Preferably, the dynamic range of the optical time domain detector is larger than 26dB, the spatial resolution is smaller than 5m, and the condition that the detection precision is too low and the damage of a small-area blind ditch cannot be determined is prevented.
Preferably, the outer surface of the detection optical fiber is provided with a rice mark, and the rice mark is used for determining the length of the detection optical fiber, so that a constructor can accurately find out a damaged position conveniently.
Preferably, still include glass steel glue, glass steel glue be used for with distributed detection optic fibre is fixed in the french drain collector pipe outer wall, glass steel glue can guarantee the deformation in coordination of detection optic fibre and french drain collector pipe when not damaging the collector pipe.
To sum up, owing to adopted above-mentioned technical scheme, the beneficial effects of the utility model are that:
1. the utility model discloses a to detect optic fibre setting on the french drain collector pipe, can fix a position the damaged position of infiltration french drain fast through the optical time domain detector, for the maintenance provides the guide, avoid the construction of large tracts of land to look for damaged point, the effectual construction cost that has reduced has improved the efficiency of construction.
2. The utility model discloses a detection of infiltration french drain damaged position and damaged degree can be realized promptly to ordinary detection optic fibre, need not lay temperature compensation optic fibre, low cost, and it is convenient to be under construction.
3. The utility model discloses an adopt the subelement to set up distributed optical fiber, single detecting element has damaged the normal use that does not influence other detecting element, can improve the fault-tolerant rate of system.
4. The utility model discloses an adopt glass steel to glue will distributed detection optic fibre is fixed in the french drain collector pipe outer wall, glass steel glue can guarantee to detect the deformation in coordination of optic fibre and french drain collector pipe when not damaging the collector pipe.
5. The utility model discloses an optical time domain reflectometer that adopts only when detecting with detect optical fiber connection, need not to place in the detection scene for a long time, can improve equipment life and utilization ratio.
Drawings
Fig. 1 is a partial structural plan view of the present invention;
FIG. 2 is a cross-sectional view of a single detection unit of the present invention;
FIG. 3 is a partial enlarged view of a cross-sectional view of a single detection unit of the present invention;
fig. 4 is a graph showing the variation of the power curve of the back rayleigh scattered light according to the present invention.
Icon: 1-detection optical fiber, 2-optical time domain detector, 3-optical fiber connector, 4-blind ditch water collecting pipe, 5-blind ditch water collecting well, 6-blind ditch base and 7-glass fiber reinforced plastic glue.
Detailed Description
The present invention will be described in detail with reference to the accompanying drawings.
In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the invention.
Example 1
As shown in fig. 1, 2 and 3, the present embodiment provides a water seepage blind ditch damage detection system based on a distributed optical fiber, which includes a distributed detection optical fiber and an optical time domain detector 2, wherein the distributed detection optical fiber is axially disposed on an outer wall of a blind ditch water collecting pipe, and in some specific embodiments, the distributed detection optical fiber further includes a glass fiber reinforced plastic cement 7, the glass fiber reinforced plastic cement 7 is used to fix the distributed detection optical fiber on an outer wall of the blind ditch water collecting pipe 4, the blind ditch water collecting pipe 4 is located above a blind ditch base 6, the detection optical fiber is fixed on the outer wall of the blind ditch water collecting pipe by using the glass fiber reinforced plastic cement 7, so that cooperative deformation of the detection optical fiber and the blind ditch water collecting pipe can be ensured without damaging the water collecting pipe, the distributed detection optical fiber includes a plurality of detection optical fibers 1 and a plurality of optical fiber splices 3, in some specific embodiments, a dynamic, the spatial resolution is less than 5m, in some specific embodiments the detection fiber comprises a fiber core, a cladding, a coating layer and a protective sleeve, and in some specific embodiments the detection fiber is a single mode fiber. The outer surface of the detection optical fiber is provided with a rice mark, the length of the optical fiber can be determined by the rice mark, and a constructor can conveniently determine the damage position of the blind ditch. In some specific embodiments the fiber core is made of a silica glass fiber or a resin plastic fiber. Detection optic fibre between the adjacent french drain sump pit can constitute a detecting element, every 1 both ends of detection optic fibre all are provided with optical fiber splice 3, many detection optic fibre 1 passes through optical fiber splice 3 establishes ties, optical fiber splice 3 sets up in french drain sump pit 5 department, and optical fiber splice sets up in the wall of a well of french drain sump pit 5 and goes out in some specific embodiments, adjacent two detection optic fibre passes through optical fiber splice establishes ties, the optical time domain detector to distributed detection optic fibre transmission light detection signal, and the receipt is followed the optical signal that distributed detection optic fibre returned, optical time domain reflectometer only be connected with detection optic fibre when detecting, need not to place in the detection scene for a long time, can improve equipment life and utilization ratio.
The operation method of the embodiment is as follows: in the initial stage of installation, the distributed detection optical fiber and the optical time domain detector 2 are connected to form a detection loop, a first back rayleigh scattered light power curve B1 of the optical fiber along the axial direction is obtained and recorded, in actual detection, a second back rayleigh scattered light power curve B2 of the optical fiber along the axial direction is obtained and recorded, the second back rayleigh scattered light power curve B2 is compared with the recorded initial first back rayleigh scattered light power curve B1, the condition that the water collecting pipe of the blind ditch is damaged is determined, and the actual physical position of the damaged position of the blind ditch is determined according to the corresponding relation between the optical path mileage and the detection optical fiber. In some embodiments, as shown in fig. 4, when the water seepage blind ditch is slightly deformed or damaged to cause the detection optical fiber to be slightly bent, the light intensity of the backward Rayleigh scattering light at the position is greatly attenuated; when the detection optical fiber is broken due to large deformation of the water seepage blind ditch, end face reflection occurs at the position; in this embodiment, the damaged condition of the blind ditch water collecting pipe is divided into three types:
the first method comprises the following steps: the power curve of the backscattered light (B2) during detection is slightly reduced (as shown in B in FIG. 4) compared with the power curve of the backscattered light (B1) at the beginning, which indicates that the optical fiber is slightly bent at the position, and the water seepage blind ditch is slightly deformed;
and the second method comprises the following steps: the power curve of the backscattered light (B2) during detection has a peak value (as shown in the position C in figure 4) compared with the power curve of the backscattered light (B1) at the beginning, which indicates that the optical fiber is broken at the position, but the optical fibers at two sides of the broken position are still tightly attached, and the water seepage blind ditch is slightly broken at the position;
and the third is that: the power curve of the backscattered light (B2) during detection is obviously reduced compared with the power curve of the backscattered light (B1) during initial detection, and the power curve of the backscattered light (B2) presents as a noise signal (as shown in D in figure 4), which indicates that the optical fiber is broken at the position, the optical fibers on two sides of the broken position are separated, and a water seepage blind ditch is seriously broken at the position;
according to the corresponding relation between the light path mileage and the detection optical fiber, the physical position of the damaged position of the blind ditch can be determined, and as shown in the position B in FIG. 4, the water seepage blind ditch at the position 400m of the light path mileage has slight deformation; c in FIG. 4 shows that the water seepage blind ditch has slight damage at the 660m position of the light path mileage; in fig. 4, D indicates that the water seepage blind ditch is slightly damaged at 1540m of the optical path mileage.
The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, as any modifications, equivalents, improvements and the like made within the spirit and principles of the present invention are intended to be included within the scope of the present invention.
Claims (6)
1. A water seepage blind ditch damage detection system based on distributed optical fibers is characterized by comprising distributed detection optical fibers and an optical time domain detector,
the distributed detection optical fibers are axially arranged on the outer wall of the blind ditch water collecting pipe and comprise a plurality of detection optical fibers and a plurality of optical fiber connectors, every two adjacent detection optical fibers are connected in series through the optical fiber connectors, the optical time domain detector is connected with the detection optical fibers through the optical fiber connectors to form a detection loop, and the optical time domain detector transmits optical detection signals to the distributed detection optical fibers and receives optical signals returned from the distributed detection optical fibers.
2. The system according to claim 1, wherein the optical time domain detector is disposed at a start end of the distributed detection optical fiber, and is configured to send an optical detection signal to an end of the distributed detection optical fiber and receive an optical signal returned by the distributed detection optical fiber.
3. The system according to claim 1, wherein the optical fiber connector is disposed at a blind drain water collecting well.
4. The system according to claim 1, wherein the optical time domain detector has a detection dynamic range greater than 26dB and a spatial resolution less than 5 m.
5. The system for detecting the damage of the water seepage blind ditch based on the distributed optical fibers as claimed in claim 1, wherein the outer surface of the detection optical fiber is provided with a rice mark.
6. The water seepage blind ditch damage detection system based on the distributed optical fiber according to any one of claims 1 to 5, characterized by further comprising glass fiber reinforced plastic glue, wherein the glass fiber reinforced plastic glue is used for fixing the distributed detection optical fiber on the outer wall of the blind ditch water collecting pipe.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115424214A (en) * | 2022-11-03 | 2022-12-02 | 之江实验室 | Quasi-distributed liquid leakage detection method and device based on plastic optical fiber and electronic equipment |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115424214A (en) * | 2022-11-03 | 2022-12-02 | 之江实验室 | Quasi-distributed liquid leakage detection method and device based on plastic optical fiber and electronic equipment |
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