Railway hot rod service performance monitoring system and evaluation method

Abstract

The invention discloses a railway hot rod service performance monitoring system and an evaluation method. The railway hot rod service performance monitoring system comprises an optical fiber sensor module and a plurality of hot rods arranged on the two sides of a railway in an array mode. The optical fiber sensor module comprises a plurality of stick sensors and a plurality of cross-stick sensors; the stick sensors extend in the length direction of the hot sticks, and the stick sensors are attached to the hot sticks respectively; the cross-rod sensors extend along the arrangement direction of the hot rods, and a single cross-rod sensor is connected with a plurality of hot rods; the stick sensor and the cross-stick sensor are temperature strain double-parameter optical fiber sensors; the stick-sticking sensor and the cross-stick sensor are connected with the temperature detection device and the strain detection device through optical cables so as to transmit temperature information and strain information of the hot stick to the temperature detection device and the strain detection device. According to the invention, the temperature and strain of the hot rod can be monitored, so that the service performance of the hot rod can be evaluated.

Description

Technical Field

[0001] The invention relates to the field of plateau railway safety monitoring, and in particular to a railway hot rod service performance monitoring system and an evaluation method. Background Art

[0002] Heat rods are widely used on both sides of the Qinghai-Tibet Railway. They are expensive to build. The hollow interior is filled with liquid ammonia. They are buried 5 meters in the soil and 2 meters above the ground. In winter, the liquid ammonia in the underground pipe evaporates into gas and floats to the top of the pipe. Under the action of cold air, the upper gaseous ammonia turns into liquid ammonia and flows back to the bottom of the pipe. The cycle is repeated to maintain the temperature of the soil. Ideally, the soil is always in a frozen state. The railway subgrade is repeatedly fatigued by train loads and freeze-thaw environments, and there is a risk of uneven subgrade settlement, which in turn leads to the risk of settlement deformation and reduced heat exchange efficiency or refrigeration efficiency of the heat rods on both sides of the railway. At present, there is little research on the evaluation of the settlement and refrigeration efficiency of heat rods, and no relevant service performance evaluation methods have been reported. Summary of the invention

[0003] Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides a railway hot rod service performance monitoring system and evaluation method, which aims to monitor the temperature and strain of the hot rod in order to evaluate the service performance of the hot rod.

[0004] Technical solution: To achieve the above-mentioned purpose, a railway hot rod service performance monitoring system of the present invention includes an optical fiber sensor module and a plurality of hot rods arranged in an array on both sides of the railway; the optical fiber sensor module includes a plurality of stick-on-rod sensors and a plurality of cross-rod sensors; the stick-on-rod sensors extend along the length direction of the hot rods, and each stick-on-rod sensor is respectively attached to each hot rod; the cross-rod sensors extend along the arrangement direction of the hot rods, and a single cross-rod sensor connects multiple hot rods; both the stick-on-rod sensors and the cross-rod sensors are temperature-strain dual-parameter optical fiber sensors; both the stick-on-rod sensors and the cross-rod sensors are connected to a temperature detection device and a strain detection device through optical cables to transmit the temperature information and strain information of the hot rod to the temperature detection device and the strain detection device.

[0005] Furthermore, the plurality of heat rods are divided into at least two linear rod groups, and the plurality of heat rods in the same linear rod group are arranged along the extension direction of the railway; the extension direction of the cross-rod sensor is consistent with the extension direction of the railway, and a single cross-rod sensor connects the plurality of heat rods in the same linear rod group.

[0006] Furthermore, the optical cable includes a series optical cable, a transition optical cable and a branch optical cable; a plurality of cross-rod sensors are connected in series through the series optical cable, a plurality of stick-rod sensors are connected to the branch optical cable, one end of the branch optical cable is connected to the plurality of cross-rod sensors in series through the transition optical cable, and the other end of the branch optical cable is connected to a temperature detection device and a strain detection device.

[0007] Furthermore, the temperature detection device is a DTS distributed temperature tester, and the strain detection device is a BOTDR distributed strain tester.

[0008] Furthermore, the temperature-strain dual-parameter optical fiber sensor comprises a silicone round rod, a temperature optical fiber and a strain optical fiber are arranged in parallel at the center of the silicone round rod, both the temperature optical fiber and the strain optical fiber are single-mode optical fibers, and the temperature optical fiber is provided with a loose sheath.

[0009] Furthermore, the length of the stick-on sensor is consistent with that of the heat rod, and the stick-on sensor is fixedly connected to the heat rod via a clamp.

[0010] Furthermore, the cross-rod sensor is connected to the portion of the heat rod exposed on the ground; a length fine-tuning mechanism is provided on the heat rod, and the length fine-tuning mechanism can fine-tune the length of the cross-rod sensor between adjacent heat rods to adapt to the thermal expansion and contraction of the optical fiber caused by temperature changes.

[0011] A method for evaluating the service performance of a railway hot rod, wherein a DTS distributed temperature tester and a BOTDR distributed strain tester demodulate the temperature and strain information sensed by a temperature-strain dual-parameter optical fiber sensor and import the information into a computer, and the computer analyzes the temperature field distribution, temperature heat exchange efficiency, strain ε and settlement displacement d of the hot rod, and then combines the analysis data to evaluate the service performance of the hot rod.

[0012] Furthermore, when calculating the strain ε of the hot rod, temperature compensation is required; after considering the temperature compensation, the calculation equation of the strain ε of the hot rod is as follows: V = K × ε + C × T; where V is the Brillouin frequency shift of the optical fiber measured by the BOTDR distributed strain tester, K is the strain sensitivity of the strained optical fiber, C is the temperature sensitivity of the strained optical fiber, and T is the temperature measured by the DTS distributed temperature tester; when one of the two adjacent hot rods settles, the calculation equation of the settlement displacement d of the hot rod is as follows: d 2 =L 1 2 -L 0 2 =(L 0 ×(1+ε)) 2 --L 0 2 ; where L 0 is the length of the cross-rod sensor between the two hot rods before settling, L 1 is the length of the cross-rod sensor between the two hot rods after settlement, and ε is the strain of the hot rod.

[0013] Furthermore, the length fine-tuning mechanism has at least two adjustment gears, each adjustment gear corresponding to the ambient temperature within a certain range; when the ambient temperature rises, the adjustment gear is correspondingly increased, shortening the length of the cross-rod sensor between adjacent heat rods; when the ambient temperature rises, the adjustment gear is correspondingly decreased, increasing the length of the cross-rod sensor between adjacent heat rods; through length fine-tuning, the length of the cross-rod sensor between adjacent heat rods can be made closer under different ambient temperatures.

[0014] Beneficial effects: The railway hot rod service performance monitoring system and evaluation method of the present invention have the following beneficial effects:

[0015] 1) Combining the temperature-strain dual-parameter optical fiber sensor, DTS distributed temperature tester and BOTDR distributed strain tester, the temperature and stress of the hot rod can be monitored, so as to analyze the temperature field distribution, temperature heat exchange efficiency, strain and settlement displacement of the hot rod, and then evaluate the service performance of the hot rod;

[0016] 2) There is a length fine-tuning mechanism on the hot rod, through which the length of the cross-rod sensor between adjacent hot rods can be fine-tuned to adapt to the thermal expansion and contraction of the optical fiber caused by changes in ambient temperature, thereby making the length information of the cross-rod sensor between adjacent hot rods more accurate, and the calculated hot rod settlement displacement is also more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Attached Figure 1 It is a schematic diagram of the overall structure of the railway hot rod service performance monitoring system of the present invention;

[0018] Attached Figure 2 It is a schematic diagram of the structure of the temperature-strain dual-parameter optical fiber sensor;

[0019] Attached Figure 3 Schematic diagram of the hot rod before and after deformation;

[0020] Attached Figure 4 Schematic diagram of the hot rod before and after sedimentation. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with the accompanying drawings.

[0022] As attached Figures 1 to 4 The railway hot rod service performance monitoring system comprises a plurality of hot rods 1 arranged in an array on both sides of the railway, and also comprises an optical fiber sensor module, wherein the optical fiber sensor module is used to monitor the temperature and stress of the hot rods 1.

[0023] The optical fiber sensor module includes a plurality of stick-on sensors 2 and a plurality of cross-rod sensors 3. The stick-on sensors 2 extend along the length direction of the heat rod 1, and each stick-on sensor 2 is attached to each heat rod 1. The cross-rod sensors 3 extend along the arrangement direction of the heat rods 1, and a single cross-rod sensor 3 connects multiple heat rods 1. Both the stick-on sensors 2 and the cross-rod sensors 3 are temperature-strain dual-parameter optical fiber sensors. Specifically, as shown in the attached figure, Figure 2 As shown in the figure, the temperature-strain dual-parameter optical fiber sensor includes a silicone round rod 9, at the center of which a temperature optical fiber 10 and a strain optical fiber 11 are arranged in parallel. Both the temperature optical fiber 10 and the strain optical fiber 11 are single-mode optical fibers, and the temperature optical fiber 10 is provided with a loose sheath. The temperature of the hot rod 1 can be measured by the temperature optical fiber 10, and the strain of the hot rod 1 can be measured by the strain optical fiber 11.

[0024] The stick sensor 2 and the cross-stick sensor 3 are both connected to the temperature detection device 4 and the strain detection device 5 through optical cables to transmit the temperature information and strain information of the hot rod 1 to the temperature detection device 4 and the strain detection device 5, so as to monitor the service performance of the hot rod 1. Specifically, the temperature detection device 4 is a DTS distributed temperature tester, and the strain detection device 5 is a BOTDR distributed strain tester. The temperature optical fiber 10 in each temperature-strain dual-parameter optical fiber sensor is connected to a temperature test optical path through an optical cable, and the temperature test optical path is connected to the DTS distributed temperature tester through an optical cable. Correspondingly, the strain optical fiber 11 in each temperature-strain dual-parameter optical fiber sensor is connected to a strain test optical path through an optical cable, and the strain test optical path is connected to the BOTDR distributed strain tester through an optical cable.

[0025] The plurality of heat rods 1 are divided into at least two linear rod groups, with at least one linear rod group on each side of the railway, and the plurality of heat rods 1 in the same linear rod group are arranged at intervals along the extension direction of the railway. Figure 1 As shown in , the extension direction of the cross-rod sensor 3 is consistent with the extension direction of the railway, and a single cross-rod sensor 3 is connected to several hot bars 1 in the same line bar group.

[0026] The optical cable is a dual-core optical cable, corresponding to the temperature optical fiber 10 and the strain optical fiber 11. The optical cable includes a series optical cable 6, a transition optical cable 7 and a branch optical cable 8. Figure 1As shown in the figure, a plurality of cross-rod sensors 3 are connected in series through a serial optical cable 6, a branch optical cable 8 is arranged on the top of the hot rod 1, and the upper ends of a plurality of stick-on sensors 2 are connected to the branch optical cable 8. One end of the branch optical cable 8 is connected to a plurality of cross-rod sensors 3 connected in series through a transition optical cable 7, and the other end of the branch optical cable 8 is connected to a temperature detection device 4 and a strain detection device 5. Thus, all stick-on sensors 2 and all cross-rod sensors 3 are connected together, so that the DTS distributed temperature tester can receive the temperature information of all temperature optical fibers 10, and the BOTDR distributed strain tester can receive the strain information of all strain optical fibers 11.

[0027] The length of the stick sensor 2 is consistent with the length of the heat rod 1, and the upper and lower ends of the stick sensor 2 are aligned with the upper and lower ends of the heat rod 1, so that the stick sensor 2 can detect the temperature of each part of the heat rod 1. Figure 3 As shown in , the stick sensor 2 is fixedly connected to the hot rod 1 through the clamp 12, so that the stick sensor 2 can deform synchronously with the hot rod 1, so that the stick sensor 2 can detect the strain of the hot rod 1.

[0028] Generally speaking, the length of the heat rod 1 is 7 meters, of which 5 meters are inserted into the soil and 2 meters are exposed on the ground. The cross-rod sensor 3 is connected to the part of the heat rod 1 exposed on the ground. Usually, the cross-rod sensor 3 is connected at a position 1 meter away from the top of the heat rod 1.

[0029] In a plateau environment, the highest and lowest temperatures in a year differ greatly, so the temperature-strain dual-parameter optical fiber sensor will have a certain thermal expansion and contraction phenomenon, which will cause the length of the sensor to change, affecting the calculation of the settlement displacement of the hot rod 1. For this reason, a length fine-tuning mechanism 13 is provided on the hot rod 1, which can fine-tune the length of the cross-rod sensor 3 between adjacent hot rods 1 to adapt to the thermal expansion and contraction of the optical fiber caused by temperature changes.

[0030] The present invention also provides a method for evaluating the service performance of a railway hot rod. The DTS distributed temperature tester and the BOTDR distributed strain tester are both connected to a computer evaluation module 14. After the temperature-strain dual-parameter optical fiber sensor transmits the measured temperature information and strain information of the hot rod 1 to the DTS distributed temperature tester and the BOTDR distributed strain tester through an optical cable, the DTS distributed temperature tester and the BOTDR distributed strain tester demodulate the temperature and strain information sensed by the temperature-strain dual-parameter optical fiber sensor and import the information into the computer evaluation module 14. The computer evaluation module 14 analyzes the temperature field distribution, temperature heat exchange efficiency, strain amount ε and settlement displacement d of the hot rod 1, and then evaluates the service performance of the hot rod 1 in combination with the analyzed data.

[0031] Among them, the temperature information of each part of the hot rod 1 can be detected by the stick sensor 2, so as to analyze the temperature field distribution and temperature heat exchange efficiency of the hot rod 1. Figure 3 As shown in , the strain of the hot rod 1 can also be detected by the stick sensor 2. Since the strain optical fiber 11 is measured by the BOTDR distributed tester to obtain the optical fiber Brillouin frequency shift v, and the optical fiber Brillouin frequency shift is affected by both temperature and strain, temperature compensation is required when calculating the strain ε of the hot rod 1; after considering temperature compensation, the calculation equation of the strain ε of the hot rod 1 is as follows:

[0032] V = K × ε + C × T;

[0033] Where V is the Brillouin frequency shift of the optical fiber measured by the BOTDR distributed strain tester, K is the strain sensitivity of the strained optical fiber 11, C is the temperature sensitivity of the strained optical fiber 11, and T is the temperature measured by the DTS distributed temperature tester. By substituting T into the above equation, the strain variable ε can be calculated, which is the strain variable after ambient temperature compensation.

[0034] Attached Figure 3 Schematic diagram of the deformation of the railway hot rod 1 of the present invention. The specific implementation method is to pre-calibrate the relationship between the strain and deformation between the clamps 12 when the hot rod 1 is deformed according to the layout position of the temperature-strain dual-parameter optical fiber sensor on the hot rod 1. In specific application, the hot rod 1 is deformed, and the temperature-strain dual-parameter optical fiber sensor is deformed in coordination with the hot rod 1 under the fixation of the clamp 12. Based on the pre-calibrated strain and deformation relationship, the deformation of the hot rod 1 is calculated from the measured strain after temperature compensation.

[0035] As attached Figure 4 As shown in , when one of the two adjacent heat rods 1 settles, the calculation equation for the settlement displacement d of the heat rod 1 is as follows:

[0036] d 2 =L 1 2 -L 0 2 =L 0 ×(1+ε) 2 --L 0 2 ;

[0037] Where L 0 is the length of the cross-rod sensor 3 between the two hot rods 1 before settling, L 1 is the length of the cross-rod sensor 3 between the two heat rods 1 after settlement, and ε is the strain of the heat rod 1.

[0038] Attached Figure 4The figure is a schematic diagram of the settlement deformation of the heat rod 1 of the present invention. The figure is a service schematic diagram of two adjacent heat rods 1 as an example. The temperature-strain dual-parameter optical fiber sensor is fixed on the heat rod 1 through a clamp 12. The distance between the two adjacent heat rods 1 is L 0 Meters, that is, the length of the temperature-strain dual-parameter optical fiber sensor between two adjacent heat rods 1 is also L 0 m. When one of the hot rods 1 undergoes a vertical settlement displacement d, the length of the temperature-strain dual-parameter optical fiber sensor becomes L 1 Meters, and at this time the strain measured by the temperature-strain dual-parameter optical fiber sensor is ε. After temperature compensation, we have L 1 =L 0 ×(1+ε), and then we get d 2 =L 1 2 -L 0 2 =L 0 ×(1+ε) 2 --L 0 2 From this, the settlement displacement d of the hot rod 1 can be calculated.

[0039] The length fine-tuning mechanism 13 has at least two adjustment gears, each of which corresponds to an ambient temperature within a certain range. When the ambient temperature rises, the adjustment gear is correspondingly increased to shorten the length of the cross-rod sensor 3 between adjacent hot rods 1; when the ambient temperature rises, the adjustment gear is correspondingly decreased to increase the length of the cross-rod sensor 3 between adjacent hot rods 1.

[0040] In plateau areas, the temperature may vary greatly in different seasons of the year and different periods of the day, and the optical fiber will undergo a certain degree of thermal expansion and contraction. Under a temperature difference of several tens of degrees, the change in the length of the optical fiber caused by the thermal expansion and contraction of the optical fiber is often ignored. Therefore, when calculating the settlement displacement of the hot rod 1, the calculation result is not accurate enough. Therefore, in the present invention, a length fine-tuning mechanism 13 is provided on the hot rod 1, and the length fine-tuning mechanism 13 is divided into a plurality of adjustment gears, for example, one adjustment gear is divided into every twenty degrees, that is, one gear from minus 40 degrees to minus 20 degrees, one gear from minus 20 degrees to 0 degrees, one gear from 0 degrees to 20 degrees, and one gear from 20 degrees to 40 degrees. In this way, by fine-tuning the length of the optical fiber between the two hot rods 1, the length of the cross-rod sensor 3 between the adjacent hot rods 1 is closer under different ambient temperatures, reducing the error caused by the change in the length of the optical fiber, so that the calculation result of the settlement displacement d of the hot rod 1 is more accurate.

[0041] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A railway hot rod service performance monitoring system, characterized by: It comprises an optical fiber sensor module and a plurality of heat rods (1) arranged in an array on both sides of a railway; The optical fiber sensor module comprises a plurality of stick-attached sensors (2) and a plurality of cross-stick sensors (3); the stick-attached sensors (2) extend along the length direction of the hot rod (1), and each stick-attached sensor (2) is attached to each hot rod (1); the cross-stick sensor (3) extends along the arrangement direction of the hot rods (1), and a single cross-stick sensor (3) is connected to a plurality of hot rods (1); The stick-on sensor (2) and the cross-rod sensor (3) are both temperature-strain dual-parameter optical fiber sensors; the stick-on sensor (2) and the cross-rod sensor (3) are both connected to a temperature detection device (4) and a strain detection device (5) via an optical cable, so as to transmit temperature information and strain information of the hot rod (1) to the temperature detection device (4) and the strain detection device (5).

2. A railway hot rod service performance monitoring system according to claim 1, characterized in that: The plurality of heat rods (1) are divided into at least two linear rod groups, and the plurality of heat rods (1) in the same linear rod group are arranged along the extension direction of the railway; The extension direction of the cross-rod sensor (3) is consistent with the extension direction of the railway, and a single cross-rod sensor (3) is connected to a plurality of hot rods (1) in the same line rod group.

3. A railway hot rod service performance monitoring system according to claim 2, characterized in that: The optical cable comprises a series optical cable (6), a transition optical cable (7) and a branch optical cable (8); a plurality of cross-rod sensors (3) are connected in series via the series optical cable (6), a plurality of stick-on sensors (2) are connected to the branch optical cable (8), one end of the branch optical cable (8) is connected to the plurality of cross-rod sensors (3) connected in series via the transition optical cable (7), and the other end of the branch optical cable (8) is connected to a temperature detection device (4) and a strain detection device (5).

4. A railway hot rod service performance monitoring system according to claim 3, characterized in that: The temperature detection device (4) is a DTS distributed temperature tester, and the strain detection device (5) is a BOTDR distributed strain tester.

5. A railway hot rod service performance monitoring system according to claim 4, characterized in that: The temperature-strain dual-parameter optical fiber sensor comprises a silicone round rod (9), a temperature optical fiber (10) and a strain optical fiber (11) are arranged in parallel at the center of the silicone round rod (9), the temperature optical fiber (10) and the strain optical fiber (11) are both single-mode optical fibers, and the temperature optical fiber (10) is provided with a loose sheath.

6. A railway hot rod service performance monitoring system according to claim 4, characterized in that: The length of the stick-on sensor (2) is consistent with the length of the hot rod (1), and the stick-on sensor (2) is fixedly connected to the hot rod (1) via a clamp (12).

7. A railway hot rod service performance monitoring system according to claim 4, characterized in that: The cross-rod sensor (3) is connected to the portion of the hot rod (1) exposed on the ground; a length fine-tuning mechanism (13) is provided on the hot rod (1), and the length fine-tuning mechanism (13) can fine-tune the length of the cross-rod sensor (3) between adjacent hot rods (1) to adapt to the thermal expansion and contraction of the optical fiber caused by temperature changes.

8. A method for evaluating the service performance of a railway hot rod according to claim 7, characterized in that: The DTS distributed temperature tester and the BOTDR distributed strain tester demodulate the temperature and strain information sensed by the temperature-strain dual-parameter optical fiber sensor and import the information into a computer evaluation module (14). The computer evaluation module (14) analyzes the temperature field distribution, temperature heat exchange efficiency, strain ε and settlement displacement d of the heat rod (1), and then combines the analysis data to evaluate the service performance of the heat rod (1).

9. A railway hot rod service performance evaluation method according to claim 8, characterized in that: When calculating the strain ε of the heat rod (1), temperature compensation is required. After considering the temperature compensation, the calculation equation of the strain ε of the heat rod (1) is as follows: V = K × ε + C × T; Wherein V is the Brillouin frequency shift of the optical fiber measured by the BOTDR distributed strain tester, K is the strain sensitivity of the strained optical fiber (11), C is the temperature sensitivity of the strained optical fiber (11), and T is the temperature measured by the DTS distributed temperature tester; When one of the two adjacent heat rods (1) sinks, the calculation equation for the sinking displacement d of the heat rod (1) is as follows: d 2 =L1 2 -L0 2 =(L0×(1+ε)) 2 --L0 2 ; Wherein L0 is the length of the cross-rod sensor (3) between the two heat rods (1) before sedimentation, L1 is the length of the cross-rod sensor (3) between the two heat rods (1) after sedimentation, and ε is the strain of the heat rod (1).

10. A railway hot rod service performance evaluation method according to claim 9, characterized in that: The length fine-tuning mechanism (13) has at least two adjustment gears, each adjustment gear corresponding to an ambient temperature within a certain range; when the ambient temperature rises, the adjustment gear is correspondingly increased, shortening the length of the cross-rod sensor (3) between adjacent hot rods (1); when the ambient temperature rises, the adjustment gear is correspondingly decreased, increasing the length of the cross-rod sensor (3) between adjacent hot rods (1); by length fine-tuning, the length of the cross-rod sensor (3) between adjacent hot rods (1) is made closer under different ambient temperatures.

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