CN201278199Y - Pipeline landslide deep displacement monitoring and early warning system based on fiber bragg grating - Google Patents

Abstract

The utility model is a monitoring and early warning system for deep displacement of pipeline landslides based on optical fiber gratings. The inclinometer tube strain fiber grating sensor (16) of the on-site landslide deep displacement monitoring device installed in the landslide in a certain structure, the earth pressure cell strain fiber grating sensor (4) of the landslide thrust monitoring device for the pipeline and the pipeline strain monitoring device The output of the tube body strain fiber grating sensor (3) is shifted in series with the automatic optical switch (6) and the fiber grating demodulator (7) of the on-site monitoring station, and the output of the upper computer (8) is connected to the automatic optical switch (6) ) input; the output of the fiber grating demodulator (7) is connected to the upper computer (8) input; the output of the upper computer (8) is connected to the GPRS transmission module (9), and the receiving terminal GPRS receiving module (10) of the office is connected to the lower computer The input of (11), the output of lower computer (11) connects alarm (12) and display.

Description

Monitoring and early warning system for deep displacement of pipeline landslide based on fiber grating

technical field

The utility model is a monitoring and early warning system for deep displacement of pipeline landslides based on optical fiber gratings. The invention relates to the technical field of stress measurement, temperature measurement and pipeline system.

Background technique

Landslide refers to the overall movement of the rock and soil mass forming the slope under the action of gravity along with the shearing process on the weak surface of the lower part. Landslide disaster is one of the main forms of geological disasters that cause loss of human life and property. Long-distance oil or gas pipelines have a transportation distance of thousands of kilometers, crossing many geological and geomorphic units, and often inevitably pass through areas with complex geological conditions, such as mountainous areas and permafrost areas. Due to insufficient line selection or landslides induced by pipeline construction or earthquakes, pipelines laid in mountainous areas may pass through active landslides, and the safe operation of pipelines is seriously threatened by these active landslides. These landslides that may threaten the safety of pipelines are called pipeline landslides.

In the history of pipeline transportation in the past forty years, geological disasters mainly caused by landslides have caused pipeline accidents many times. Among the Western European pipeline accidents investigated by the European Natural Gas Pipeline Accident Data Group (EGIG) from 1970 to 2001, 7% were caused by geological disasters; the natural gas transmission data from the US Department of Transportation from 1984 to 2001 showed that 8.5% of the accidents were Caused by geological hazards; Canada's National Energy Council survey shows that 12% of pipeline accidents affecting Canadian operations are caused by geological hazards. In March 1987, a huge landslide caused by an earthquake caused a 40km-long fracture of the Trans-Ecuador pipeline, which stopped the pipeline for two weeks and caused an economic loss of US$700 million. In the winters of 1995 and 1996, three pipelines of the Northwest Gas Pipeline in the United States ruptured due to landslides induced by extremely heavy rainfall in western Washington.

my country's pipeline industry is developing vigorously. Most of these pipelines transport the abundant oil and natural gas in the west of my country to the east of my country. However, most of the mountainous areas in my country are concentrated in the west and southwest of my country. The pipelines will inevitably pass through geological disaster-stricken areas. The Zhongxian-Yichang 409-kilometer section of the Zhongxian-Wuhan Gas Pipeline is located in the mountainous area of eastern Chongqing and western Hubei. There are many mountains and peaks, with significant elevation differences. The terrain and geological conditions are complex. There are many groups of geological disaster-prone rock formations, which are frequent occurrences of landslides and dangerous rock collapses. hair lot. The Lanzhou-Guangyuan section of the Lanchengyu-Chongqing Refined Products Pipeline, which was completed and put into operation in 2003, has an active structure, broken lithology, and well-developed terrain. After it was put into production, a huge amount of money was invested in the prevention and control of geological disasters. However, the survey in 2007 showed that geological disasters threatened the safety of the pipeline. There are still as many as 530 places. The total length of the West-East Gas Pipeline Project is about 4,000 kilometers, and it is seriously threatened by various geological disasters, among which 39 landslide disasters have been identified.

In the face of numerous pipeline landslide disasters, my country's pipeline operating companies often take active engineering control measures, but these measures also have some disadvantages, first of all, the high cost, and secondly, the prevention and control projects are not "once and for all", and the design and construction are uncertain. There are many factors, and the management cycle is long. Monitoring is an efficient and low-cost prevention and control measure. The Italian SNAM company regards monitoring pipelines as the main way to prevent landslide disasters. They have monitored pipelines for as long as 30 years and successfully avoided a large number of pipeline accidents. Landslides have also been effectively monitored after my country's West-East Gas Pipeline, Zhongwu Line and other pipelines have been put into operation.

The traditional deep displacement monitoring of landslides mainly adopts multi-point displacement meters or borehole inclinometers, which have poor real-time performance and cannot meet the long-term and real-time requirements of landslide monitoring.

Coaxial cable technology has advantages in terms of cost and real-time monitoring when used to monitor the deep displacement of landslides. However, the outer diameter of the coaxial cable is small (about 10mm), and it is difficult to coordinate the deformation of the cable and the soil after buying the soil, resulting in simultaneous The shaft cable cannot really reflect the deformation of the landslide body.

As a new technology, distributed optical fiber technology has been applied to landslide monitoring. This technology has advantages in precision and automatic monitoring. However, when this technology monitors the deep displacement of landslides, its vertical positioning accuracy is poor (about 1m). There are also certain limitations in terms of monitoring.

Utility model content

The purpose of the utility model is to design a monitoring and early warning system for the deep displacement of pipeline landslides based on optical fiber gratings with precise positioning, high spatial resolution and low cost.

The utility model proposes a pipeline landslide deep displacement monitoring and early warning system based on fiber grating sensing technology. This system uses fiber optic grating sensing technology to jointly monitor the landslide and the pipeline under its influence. The monitoring content includes the displacement monitoring of the deep part of the landslide, the thrust monitoring of the landslide on the pipeline and the strain monitoring of the pipeline. A monitoring system was built to realize real-time automatic data collection, remote transmission and automatic analysis.

Fiber Bragg Grating (Fiber Bragg Grating, FBG, referred to as fiber grating) is a micro-optical component that has been developed rapidly in the past 20 years, and is made by using the photosensitivity in the optical fiber. The so-called photosensitivity in the optical fiber refers to the characteristic that the refractive index of the optical fiber will change correspondingly with the spatial distribution of light intensity when the laser passes through the doped optical fiber. The essence of the spatial phase grating formed in the fiber core is to form a narrow-band (transmission or reflection) filter or mirror in the fiber core.

Fiber Bragg grating sensor is a wavelength selective reflector carved by optical fiber, the central wavelength λ _B of the back reflected light is related to the grating period Λ and the refractive index n _eff of the fiber core, namely

λ _B = 2n _eff Λ

The basic principle of FBG fiber Bragg grating sensing is that when the temperature, strain, stress or other physical quantities to be measured around the grating change, it will cause the change of the grating period or the refractive index of the fiber core, so that the center wavelength of the fiber Bragg grating will be shifted by Δλ _B. By detecting the displacement of the wavelength of the grating, the change of the physical quantity to be measured can be obtained. Right now

Δλ _B = K _ε · Δε + K _T · ΔT

In the formula, K _ε is the sensitivity coefficient of strain sensing, and K _T is the sensitivity coefficient of fiber grating temperature sensing.

For the case where the FBG core is pure silica, K _ε is 1pm/uε, and K _T is 10pm/℃. Optical fiber material, writing process and packaging material will all affect the strain and temperature sensing sensitivity coefficient of FBG, and the above parameters must be calibrated before application.

Fiber gratings can be made into various sensor devices and are widely used in the sensing field. Compared with traditional electrical sensors, fiber grating sensors have their own unique advantages: 1. The sensor head is simple in structure, small in size, light in weight, and variable in shape, suitable for embedding in various large structures, and can measure the stress inside the structure , strain and structural damage, etc., with good stability and repeatability; 2. There is natural compatibility with optical fibers, easy to connect with optical fibers, low optical loss, good spectral characteristics, and high reliability; 3. Non-conductive, It has little influence on the measured medium, and has the characteristics of anti-corrosion and anti-electromagnetic interference, and is suitable for working in harsh environments; 4. Lightweight and soft, multiple gratings can be written in one optical fiber to form a sensing array, and WDM The combination of multiplexing and time-division multiplexing systems realizes distributed sensing; 5. The measurement information is encoded in wavelength, so the fiber grating sensor is not affected by factors such as light intensity fluctuations of the light source, optical fiber connection and coupling loss, and changes in the polarization state of light waves. , With strong anti-interference ability; 6. High sensitivity, high resolution.

Compared with the widely used Brillouin optical time domain reflectometer BOTDR, the advantages of the fiber grating sensor are: 1. The measurement point can be accurately positioned and the resolution is high; 2. The cost is low; 3. The sensing part can be processed , Encapsulation, making it more suitable for the harsh environment on site.

Due to these advantages, in the field of geotechnical engineering, fiber grating sensors are easy to embed in rock and soil for high-resolution and wide-range measurement of internal strain and temperature. The technical advantages are very obvious, especially in the ability to obtain long-term, Reliable deformation data of rock and soil mass. At present, fiber grating sensing technology has not been used for deep displacement monitoring of landslides.

The pipeline landslide deep displacement monitoring and early warning system based on fiber grating sensing technology proposed by the utility model is shown in Fig. 1 . Since the deep displacement of the landslide will inevitably produce a thrust on the pipeline, and then strain on the pipeline, the system is divided into three parts: the displacement monitoring of the deep part of the landslide, the thrust of the landslide on the pipeline, and the pipeline strain monitoring device.

The monitoring of the deep displacement of the pipeline landslide is to monitor the side of the inclinometer tube 1 facing the sliding direction of the landslide body under the maximum tensile strain when the landslide body slides and the inclinometer tube 1 is bent by the thrust of the landslide body, and the direction along the sliding direction of the landslide body is monitored. One side of the inclinometer tube 1 bears the maximum compressive strain; specifically, the inclinometer tube 1 pasted with the fiber Bragg grating sensor 16 of the inclinometer tube faces the potential sliding direction of the landslide on the landslide body along the lead Insert in the vertical direction through all potential sliding surfaces and extend to the borehole 3-5m below the bedrock surface; connect the optical fiber connector with the optical cable, and lead the signal to the monitoring station through the optical cable 5; at the monitoring station, the upper computer 8 calls the automatic The compiled program controls the fiber grating demodulator 7 to realize real-time automatic data collection; the maximum tensile strain borne by the inclinometer tube 1 can be measured. Assuming that the inclinometer tube 1 in the bedrock is fixed and constrained, the bending deflection of the inclinometer tube 1 can be calculated through the tensile strain distribution of the inclinometer tube 1 by using the double integral algorithm, and this deflection is the deep displacement of the landslide quantity.

The formula for measuring the bending deflection of the inclined pipe (displacement in the deep part of the landslide) using the double integral algorithm is as follows:

$\mathrm{<span\; class="notranslate">\; the\; y</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; \&Integral;</span><span\; class="notranslate">\; (</span><span\; class="notranslate">\; \&Integral;</span>\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; dx</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; dx</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; c</span>}$

In the formula:

ε——the bending strain of the inclinometer pipe measured by the FBG sensor;

y—the deflection of the inclinometer tube at the depth position x (calculated from the top of the bedrock) (deep displacement of the landslide);

r——the outer diameter of the inclinometer tube;

ε(x)—bending strain of the inclinometer tube at x, the strain tube at x=L is unconstrained, ε=0;

c——Integral constant, the inclinometer tube is fixed at x=0, so c=0.

Fiber Bragg grating sensors are distributed along the depth direction of the strain tube, and the strain ε(x) between the measurement points is obtained by the method of cubic spline function difference or linear interpolation. The ε(x) between each point may be different, and the deep displacement y is essentially a piecewise integral function.

The principle of the pipeline landslide deep displacement monitoring and early warning system is shown in Figure 3. It is composed of the landslide deep displacement monitoring device, the landslide thrust monitoring device on the pipeline, the pipeline strain monitoring device, the on-site monitoring station, and the receiving terminal in the office. The inclinometer tube strain fiber grating sensor 16 of the on-site landslide deep displacement monitoring device installed in the landslide in a certain structure, the soil pressure cell strain fiber grating sensor 4 of the landslide thrust monitoring device for the pipeline, and the pipe body strain of the pipeline strain monitoring device The output of the fiber grating sensor 3 is connected to the automatic optical switch 6 of the on-site monitoring station, the output of the automatic optical switch 6 is connected to the input of the fiber grating demodulator 7, and the output of one end of the upper computer 8 is connected to the input of one end of the automatic optical switch 6; The output of the grating demodulator 7 is also connected to the input of the upper computer 8; the output of the upper computer 8 is connected to the GPRS transmission module 9, and the receiving terminal GPRS receiving module 10 of the office is connected to the input of the lower computer 11, and the output of the lower computer 11 is connected to the alarm 12 and monitor.

The electrical principle of the system is shown in Figure 4. Three FBG sensors are used to monitor the deep displacement of the landslide, the thrust of the landslide on the pipeline and the strain of the pipeline—the FBG sensor 16 for the inclinometer tube, the FBG sensor 4 for the soil pressure box, and the FBG sensor for the pipe. The PC connector of the volume fiber grating sensor 3 is connected to the PC connector of the optical switch 6 with an optical fiber, and the R232 of the optical switch 6 is directly connected to the R232 of the upper computer 8, and the PC connector of the optical switch 6 is connected to the CH1 of the fiber grating demodulator 7SM125 end, the LAN port of the fiber grating demodulator 7SM125 is connected to the LAN port of the upper computer 8, the R232 port of the upper computer 8 is connected to the R232 port of the GPRS transmission module 9 Siemens MC35i, and the GPRS transmission module 9 is received by GPRS through the antenna GSM and GPRS network After module 10 antenna GSM receives, R232 is connected to R232 of lower computer 11, the output of lower computer 11 is connected to R232 of alarm 12DS-7400 by R232, and the output of lower computer 11 is connected to the VGA end of display by VGA terminal.

The output signals of the three fiber grating sensors that monitor the deep displacement of the landslide, the thrust of the landslide on the pipeline, and the strain of the pipeline are conducted to the fiber grating demodulator 7 one by one, and the fiber grating demodulator 7 demodulates the central wavelength of each fiber grating sensor The displacement is output to the host computer 8, and the cycle of the conduction signal of the optical switch 6 to the fiber grating demodulator 7 is controlled by the host computer 8. The upper computer 8 automatically calculates each monitoring quantity and sends it to the GPRS transmission module 9 and accepts the signal of the GPRS transmission module 9 for control. The terminal GPRS receiving module 10 can also accept the signal of the receiving terminal, send it to the lower computer 11 for processing, display it on the display and give an alarm by the alarm device 12 .

The composition of the landslide deep displacement monitoring device is shown in Figure 3. The output of the inclinometer tube fiber optic grating sensor 16 of the inclinometer tube 1 is connected to the input of the optical switch 6, and the output of the optical switch 6 is connected to the input of the fiber Bragg grating demodulator 7. The output of the demodulator 7 is connected to the host computer 8 on site. And the fiber grating sensor 16 of the inclinometer tube on the inclinometer tube 1 is to form a sensor group composed of series fiber grating sensors and directly paste it on the outside of the axial direction of the inclinometer tube 1. to the connecting fiber. Put the inclinometer tube 1 pasted with the fiber grating sensor in the borehole of the landslide 13, and when lowering, the side of the inclinometer tube 1 glued with the inclinometer tube fiber grating sensor 16 faces the potential sliding direction of the landslide. Connect the optical fiber connector to the optical cable 5, and lead the signal to the monitoring station through the optical cable 5; at the monitoring station, the host computer 8 invokes the self-edited program to control the fiber grating demodulator 7 to realize real-time automatic data collection.

The working principle of this device is such that when the landslide 13 slides down the sliding surface 15, the inclinometer tube 1 is bent by the thrust of the landslide 13, and the side of the inclinometer tube 1 facing the sliding direction of the landslide 13 bears the maximum tensile strain , the side of the inclinometer tube 1 along the sliding direction of the landslide 13 bears the maximum compressive strain. The inclinometer tube fiber grating sensor 16 group placed on the inclinometer tube 1 facing the sliding direction of the landslide 13 can measure the maximum tensile strain that the inclinometer tube bears. Assuming that the inclinometer tube 1 in the bedrock is fixed and constrained, the bending deflection of the inclinometer tube 1 can be calculated through the tensile strain distribution of the inclinometer tube 1 by using the double integral algorithm, and this deflection is the deep displacement of the landslide quantity.

in:

The inclinometer tube fiber optic grating sensor 16 is divided into two types: axial strain measurement and temperature measurement; the inclinometer tube fiber optic grating sensor 16 for axial strain measurement is pasted on the outer wall of the inclinometer tube 1 with quick-drying glue, and then sealed with foam sealant The fiber grating sensor 16 for the inclinometer tube avoids direct contact between the fiber Bragg grating sensor 16 for the inclinometer tube and the surrounding rock and soil; The fiber grating sensor is only sensitive to temperature, and it is used for temperature compensation of 16 groups of fiber grating strain sensors in the inclinometer tube, and is not affected by the deformation of the inclinometer tube;

The optical fiber grating sensors 16 of the inclinometer tube are pasted at equal intervals, and the pasting distance is reduced near the potential sliding surface;

The inclinometer tube 1 is made of ABS or PVC;

The connecting optical fiber of the inclinometer tube fiber grating sensor 16 is arranged in the groove engraved on the outer wall of the inclinometer tube 1 to prevent the fiber from being scratched by the wall of the borehole during the lowering of the inclinometer tube.

The installation structure of the system inclinometer tube fiber grating sensor 16 in the landslide is as follows:

1) Use geological drilling technology to drill holes on the landslide 13 to be monitored. The holes need to pass through all potential sliding surfaces 15 and extend to 3-5m below the bedrock surface; 1°, full casing retaining wall except bedrock hole during drilling;

2) Before lowering the inclinometer pipe 1, carry out hole cleaning operations in the borehole until the muddy water becomes clear water;

3) Paste a fiber grating strain gauge on the outer wall of the first inclinometer tube 1, and cut a groove on the outer wall of the inclinometer tube 1, and fix the connecting optical fiber in the groove with adhesive tape; in order to verify the monitoring results of this device, put The optical fiber grating sensor group is pasted in a certain plane where the cross guide groove on the inner wall of the inclinometer 1 is located, so that the deformation monitored by the optical fiber grating is consistent with the deformation measured by the inclinometer;

4) After all the inclinometer tubes 1 are lowered into the holes, adjust the direction of the guide groove so that the direction of the guide groove and the direction of the 16 groups of fiber grating strain sensors of the inclinometer tube are facing the displacement direction of the landslide body;

5) Inject M5 fine sand cement mortar into the gap between the bedrock and the inclinometer tube 1, and guide the mortar with the grouting tube, and start grouting when the grouting tube is down to 1m from the bottom of the hole; between the soil and the inclinometer tube 1 Backfill fine sand in the gap;

6) Make a concrete pier at the hole, and bury a steel sleeve in the pier to protect the signal connectors of the 16 groups of optical fiber grating strain sensors in the inclinometer tube; connect the optical fiber signal connectors to the optical cable 5, and lead the signal to the monitoring station through the optical cable 5 .

The composition of the thrust monitoring device of the landslide to the pipeline is as shown in Figure 6. It is an earth pressure box for monitoring the thrust of the pipeline 14 by the landslide 13. The output of the fiber grating sensor 4 is connected to the input of the optical switch 6, and the output of the optical switch 6 is connected to the grating demodulator 7. The input and the output of the grating demodulator are connected to the on-site host computer 8 . And the fiber grating sensor of landslide 13 to pipeline 14 thrust monitoring adopts fiber grating package earth pressure box fiber grating sensor 4; 4. The sensitive surface that feels the pressure faces the sliding direction of the landslide 13. In this way, the pressure measured by the earth pressure and fiber grating sensor 3 is the frontal thrust of the landslide 13 on the pipeline 14 .

The composition of the landslide thrust monitoring device for the pipeline, the soil pressure box fiber Bragg grating sensor 4 is shown in Figure 6, the soil pressure box fiber Bragg grating sensor 4 is fixed on the pipeline 14 through the earth pressure box bracket 21, and the earth pressure box fiber Bragg grating sensor 4 feels the pressure The sensitive surface faces the sliding direction of the landslide 13. In this way, the pressure measured by the earth pressure and fiber grating sensor 4 is the frontal thrust of the landslide 13 on the pipeline 14 . The earth pressure cell support 21 is composed of two arc-shaped steel plate clamps, one of which is welded with a base, and the fiber grating sensor 4 of the earth pressure cell is embedded in the base, and a certain margin is maintained so that the earth pressure cell can Transform freely. The clip connectors 23 at both ends of the earth pressure cell support 21 are connected by nuts. When the landslide 13 slides, the thrust of the landslide 13 to the earth pressure cell can be measured by the earth pressure cell fiber grating sensor 4, and the soil body self-weight pressure that the earth pressure cell fiber grating sensor 4 bears is subtracted from the measured value, which is the deformation of the landslide 13. Thrust generated by pipeline 14.

As shown in Figure 7 and Figure 8, the monitoring device for pipe body stress is to arrange a pipe monitoring section at the edge of both sides of the landslide and the center of the landslide, and arrange 3 pipe body evenly around the periphery of each monitoring section of the pipe 14 The fiber grating sensor 3 and the three tube fiber grating sensors 3 are arranged on a plane perpendicular to the axis of the pipeline 14 . The output of the tube fiber grating sensor 3 is connected to the input of the optical switch 6, the output of the optical switch 6 is connected to the input of the fiber grating demodulator 7, and the output of the fiber grating demodulator 7 is connected to the on-site host computer 8.

The electrical principle of the single channel of the device is shown in Figure 4. The PC connector of the tube fiber grating sensor 3 is connected with the PC connector of the optical switch 6 with an optical fiber. The PC connector of the switch 6 is connected to the CH1 end of the fiber grating demodulator 7SM125, and the LAN port of the fiber grating demodulator 7SM125 is connected to the LAN port of the upper computer 8.

Pipe Stress Monitoring Device The composition of the pipe fiber grating sensor 3 is shown in Figures 7 and 8. A pipe monitoring section is arranged on both sides of the landslide and at the center of the landslide, and the distance between the monitoring sections should not exceed 60m. Three tube fiber grating sensors 3 are evenly arranged on the outer periphery of each monitoring section of the pipeline 14 and the three tube fiber grating sensors 3 are arranged on a plane perpendicular to the axis of the pipeline 14 . When installing the tube fiber grating sensor 3, scrape off the anticorrosion layer of the tube 14 completely, and polish the surface of the tube 14 until smooth, and paste the tube fiber grating sensor package 24 with the quick-drying adhesive 3 to package the tube fiber grating sensor 3. After the three tube fiber grating sensors 3 are all pasted, lead the lead fibers of the tube fiber grating sensors 3 to the ground and protect them.

When the pipeline 14 is axially subjected to tensile/compressive stress, the three pipe fiber grating sensors 3 are subjected to tensile/compressive strain; according to a certain algorithm, the maximum strain on the section of the pipeline 14 can be calculated from the three strains in the section. size and position. Based on the elastic theory of steel, the maximum tensile/compressive stress on the section of the pipe 14 can be obtained. The selection of the monitoring section is very important to the monitoring effect.

A large number of studies have shown that the key performance of the stress of the landslide 13 on the pipeline 14 is in the axial direction, and the measurement of the axial stress of the pipeline 14 can better determine the acceptable stress state of the pipeline 14. Therefore, the tube fiber grating sensor 3 only measures the axial strain of the tube 14 .

The on-site monitoring station is set up at the landslide site, including optical fiber junction box, connecting optical cable 5, optical switch 6, fiber grating demodulator 7, host computer 8, GPRS transmission module 9; the optical fiber junction box and connecting optical cable of each fiber grating sensor 5 Connect the fiber grating sensors at various positions on the landslide 13 to the optical switch 6 of the monitoring station, the output of the optical switch 6 is connected to the fiber grating demodulator 7, the output of the fiber grating demodulator 7 is connected to the host computer 8, and the output of the host computer 8 Connect GPRS transmission module 9. The optical fiber junction box and connecting optical cable 5 of each optical fiber grating sensor centrally transmit the optical fiber grating sensor signals at various positions on the landslide 13 to the optical switch 6 of the monitoring station, and the optical switch 6 sequentially converts the signals of each channel to the optical fiber grating demodulator 7. The fiber grating demodulator 7 demodulates the central wavelength displacement of each fiber grating sensor to the host computer 8, and the host computer 8 automatically calculates each monitoring value and sends it to the GPRS transmission module 9 and receives the signal of the GPRS transmission module 9 for control The GPRS transmission module 9 transmits the monitoring quantities calculated by the upper computer 8 to the receiving terminal located in the office through the public wireless communication network, and can also accept the signal of the receiving terminal and send it to the lower computer 11.

in:

Optical switch 6: Since there are many fiber grating sensors for monitoring landslides and pipelines, and there are many signal channels, it is impossible to connect to the fiber grating demodulator 7 at one time, and the optical switch 6 is used to sequentially convert the signals of each channel to the fiber grating demodulator 7 Analysis; the optical transfer switch 6 selects a commercially available product;

Fiber Bragg grating demodulator 7: used to demodulate the center wavelength displacement of each fiber Bragg grating sensor; select commercially available products;

Host computer 8 and program: used to control the demodulation frequency of the fiber grating demodulator 7, and automatically calculate each monitoring quantity from the central wavelength displacement amount demodulated by the fiber grating demodulator 7, such as the deep displacement of the landslide, surface The position displacement, the maximum strain of the pipe body, etc., send the monitoring data to the GPRS transmission module 9, and receive the signal of the GPRS transmission module 9 for control; the upper computer 8 selects commercially available products, and the program is self-edited;

GPRS transmission module 9: used to transmit each monitoring quantity calculated by the upper computer 8 to the receiving terminal located in the office through the public wireless communication network, and also accept the signal of the receiving terminal and send it to the lower computer 11.

The receiving terminal located in the office includes the following 2 parts:

1) GPRS receiving module 10, used for receiving the monitoring amount that the on-site monitoring station GPRS transmission module 9 sends, and transmits to the terminal lower computer 11, also can send feedback instruction to the on-site GPRS transmission module 9;

2) The lower computer 11 and the program are used to download the signal of the terminal GPRS receiving module 10, and call the program to carry out automatic analysis, compare the analysis result with the alarm threshold, and implement the alarm when necessary;

3) The alarm 12 is used to generate an audible warning signal when the analysis result exceeds the alarm threshold; the alarm 12 is controlled by the lower computer 11 and the program.

The working principle of the system is as follows: when the landslide 13 slides, the inclinometer tube 1 buried in the deep part of the landslide 13 is subjected to bending strain due to the thrust of the landslide 13 soil, and the inclinometer tube fiber grating sensor 16 on the inclinometer tube 1 senses To the tensile strain, the horizontal displacement on the inclinometer tube can be obtained through calculation, that is, the horizontal displacement of the deep part of the landslide 13; at the same time, the sliding of the landslide 13, the thrust generated by the pipeline is measured by the earth pressure fiber grating sensor 4, and finally the pipeline The body strain is measured by the tube fiber grating sensor 3. By connecting the optical cable 5, the sensor signal on the landslide is transmitted to the optical switch 6, and the optical switch 6 converts the signal to the fiber grating demodulator 7, and the fiber grating demodulator 7 demodulates the center wavelength displacement of the sensor wavelength and transmits it To the upper computer 8, the upper computer 8 automatically calculates the central wavelength displacement amount demodulated by the demodulator as the monitoring amount, and sends the monitoring amount to the on-site GPRS transmission module 9, and the GPRS transmission module 9 transmits the signal through the public wireless communication network To the terminal GPRS receiving module 10, the terminal GPRS receiving module 10 sends to the terminal lower computer 11, and the terminal lower computer 11 compares the monitoring quantity with the alarm threshold, and gives an alarm when necessary.

The advantages of this system are as follows:

1) Apply fiber Bragg grating sensing technology to the deep displacement monitoring of pipeline landslide 13. This technology is sometimes obvious in anti-interference, corrosion resistance, and easy networking; by constructing a specific carrier, it is possible to monitor the deep part of the landslide with fiber Bragg grating sensing technology Displacement, compared with the traditional technical means of monitoring the deep displacement of landslides, fiber grating sensing technology is easy to realize automatic real-time monitoring, and the cost is lower;

2) Precise positioning and high spatial resolution;

3) The monitoring quantity is realized by fiber grating sensing technology, which is easy to build a monitoring system, realize real-time automatic collection analysis and remote release of pipeline landslide deep displacement monitoring data, remote real-time automatic alarm; avoid tedious manual data collection, reduce Alarm time, which is crucial to the adoption of pipeline emergency measures.

Description of drawings

Figure 1 Schematic diagram of the structure of the pipeline landslide deep displacement monitoring and early warning system based on fiber gratings

Fig. 2 Diagram of monitoring and early warning system for deep displacement of pipeline landslide based on fiber grating

Figure 3 Principle block diagram of the landslide deep displacement monitoring system

Figure 4 Electrical schematic diagram of the landslide deep displacement monitoring system

Fig. 5 Comparison of the monitoring results of the deep displacement of the landslide and the monitoring results of the movable borehole inclinometer

Figure 6 Earth pressure fiber grating sensor installation structure diagram

Figure 7 Installation structure diagram of tube fiber grating sensor (cross-sectional view)

Figure 8 Installation structure diagram of tube fiber grating sensor

1-inclinometer tube

3-Tube Fiber Bragg Grating Sensor 4-Earth Pressure Cell Fiber Bragg Grating Sensor

5-Optical cable 6-Optical switch

7-fiber grating demodulator 8-host computer

9-GPRS transmission module 10-GPRS receiving module

11-lower computer 12-alarm

13-landslide 14-pipeline

15-Sliding surface 16-Fiber grating sensor for inclinometer tube

18-Slope

21-earth pressure box bracket 22-bracket clamp

23-clamp connector 24-tube fiber grating sensor package

Detailed ways

Embodiment. This example is a test system, and it is tested on a slow-moving landslide body with a width of 300m, a landslide thickness of 29m, and a base covering section that is the sliding surface. The structure of the pipeline landslide deep displacement monitoring and early warning system is shown in Figure 1, and the electrical principle block diagram is shown in Figure 3. It is composed of a landslide deep displacement monitoring device, a landslide thrust monitoring device for pipelines, a pipeline strain monitoring device, an on-site monitoring station, and a receiving terminal in the office. The inclinometer tube strain fiber grating sensor 16 of the on-site landslide deep displacement monitoring device installed in the landslide in a certain structure, the soil pressure cell strain fiber grating sensor 4 of the landslide thrust monitoring device for the pipeline, and the pipe body strain of the pipeline strain monitoring device The output of the fiber grating sensor 3 is connected to the automatic optical switch 6 of the on-site monitoring station, the output of the automatic optical switch 6 is connected to the input of the fiber grating demodulator 7, and the output of one end of the upper computer 8 is connected to the input of one end of the automatic optical switch 6; The output of the grating demodulator 7 is also connected to the input of the upper computer 8; the output of the upper computer 8 is connected to the GPRS transmission module 9, and the receiving terminal GPRS receiving module 10 of the office is connected to the input of the lower computer 11, and the output of the lower computer 11 is connected to the alarm 12 and monitor.

The electrical principle of the system is shown in Figure 4. Three FBG sensors are used to monitor the deep displacement of the landslide, the thrust of the landslide on the pipeline and the strain of the pipeline—the FBG sensor 16 for the inclinometer tube, the FBG sensor 4 for the soil pressure box, and the FBG sensor for the pipe. The PC connector of the volume fiber grating sensor 3 is connected to the PC connector of the optical switch 6 with an optical fiber, and the R232 of the optical switch 6 is directly connected to the R232 of the upper computer 8, and the PC connector of the optical switch 6 is connected to the CH1 of the fiber grating demodulator 7SM125 end, the LAN port of the fiber grating demodulator 7SM125 is connected to the LAN port of the upper computer 8, the R232 port of the upper computer 8 is connected to the R232 port of the GPRS transmission module 9 Siemens MC35i, and the GPRS transmission module 9 is received by GPRS through the antenna GSM and GPRS network After module 10 antenna GSM receives, R232 is connected to R232 of lower computer 11, the output of lower computer 11 is connected to R232 of alarm 12DS-7400 by R232, and the output of lower computer 11 is connected to the VGA end of display by VGA terminal.

The output signals of the three fiber grating sensors that monitor the deep displacement of the landslide, the thrust of the landslide on the pipeline, and the strain of the pipeline are conducted to the fiber grating demodulator 7 one by one, and the fiber grating demodulator 7 demodulates the central wavelength of each fiber grating sensor The displacement is output to the host computer 8, and the cycle of the optical switch 6 conducting the signal to the fiber grating demodulator 7 is controlled by the host computer 8. The upper computer 8 automatically calculates each monitoring quantity and sends it to the GPRS transmission module 9 and accepts the signal of the GPRS transmission module 9 for control. The terminal GPRS receiving module 10 can also accept the signal of the receiving terminal, send it to the lower computer 11 for processing, display it on the display and give an alarm by the alarm device 12 .

The composition of the landslide deep displacement monitoring device is shown in Figure 3. The output of the inclinometer tube fiber optic grating sensor 16 of the inclinometer tube 1 is connected to the input of the optical switch 6, and the output of the optical switch 6 is connected to the input of the fiber Bragg grating demodulator 7. The output of the demodulator 7 is connected to the host computer 8 on site. And the fiber grating sensor 16 of the inclinometer tube on the inclinometer tube 1 is to form a sensor group composed of series fiber grating sensors and directly paste it on the outside of the axial direction of the inclinometer tube 1. to the connecting fiber. Put the inclinometer tube 1 pasted with the fiber grating sensor in the borehole of the landslide 13, and when lowering, the side of the inclinometer tube 1 glued with the inclinometer tube fiber grating sensor 16 faces the potential sliding direction of the landslide. Connect the optical fiber connector to the optical cable 5, and lead the signal to the monitoring station through the optical cable 5; at the monitoring station, the host computer 8 invokes the self-edited program to control the fiber grating demodulator 7 to realize real-time automatic data collection.

in:

The inclinometer tube fiber optic grating sensor 16 is divided into two types: axial strain measurement and temperature measurement; the inclinometer tube fiber optic grating sensor 16 for axial strain measurement is pasted on the outer wall of the inclinometer tube 1 with quick-drying glue, and then sealed with foam sealant The fiber grating sensor 16 for the inclinometer tube avoids direct contact between the fiber Bragg grating sensor 16 for the inclinometer tube and the surrounding rock and soil; The fiber grating sensor is only sensitive to temperature, and it is used for temperature compensation of 16 groups of fiber grating strain sensors in the inclinometer tube, and is not affected by the deformation of the inclinometer tube;

The optical fiber grating sensors 16 of the inclinometer tube are pasted at equal intervals, and the pasting distance is reduced near the potential sliding surface;

The inclinometer tube 1 is made of ABS or PVC;

The connecting optical fiber of the inclinometer tube fiber grating sensor 16 is arranged in the groove engraved on the outer wall of the inclinometer tube 1 to prevent the fiber from being scratched by the wall of the borehole during the lowering of the inclinometer tube.

The electrical principle of the single channel of the device is shown in Figure 4. The PC connector of the inclinometer tube fiber grating sensor 16 for monitoring the deep displacement of the landslide is connected to the PC connector of the optical switch 6 with an optical fiber, and the R232 of the optical switch 6 is directly connected to the host computer. R232 of 8, the PC connector of optical switch 6 is connected to the CH1 end of the fiber grating demodulator 7SM125, and the LAN port of the fiber grating demodulator 7SM125 is connected to the LAN port of the host computer 8.

in:

Fiber Bragg grating sensor: select the fiber grating sensor designed and packaged by ourselves.

The optical switch selects Guanglong SUM-FSW;

The grating demodulator selects SM125.

Specifically, the fiber grating sensors connected in series to form a sensor group are directly pasted on the outside of the axial direction of the inclinometer tube 1, and pasted at equal intervals according to the axial strain and temperature measurements, and the pasting distance is reduced to 0.8 meters near the potential sliding surface; The lead fiber of each fiber grating sensor is fused and then connected to the connecting fiber; then the inclinometer tube 1 with the fiber grating sensor attached is put into the borehole on the landslide body, and the inclinometer tube 1 is glued with a fiber grating sensor when it is lowered. The side faces the potential sliding direction of the landslide; connect the optical fiber connector with the optical cable, and lead the signal to the monitoring station through the optical cable.

The working principle of this device is such that when the landslide 13 slides down the sliding surface 15, the inclinometer tube 1 is bent by the thrust of the landslide 13, and the side of the inclinometer tube 1 facing the sliding direction of the landslide 13 bears the maximum tensile strain , the side of the inclinometer tube 1 along the sliding direction of the landslide 13 bears the maximum compressive strain. The inclinometer tube fiber grating sensor 16 group placed on the inclinometer tube 1 facing the sliding direction of the landslide 13 can measure the maximum tensile strain that the inclinometer tube bears. Assuming that the inclinometer tube 1 in the bedrock is fixed and constrained, the bending deflection of the inclinometer tube 1 can be calculated through the tensile strain distribution of the inclinometer tube 1 by using the double integral algorithm, and this deflection is the deep displacement of the landslide quantity.

The installation structure of the landslide deep displacement monitoring device in the landslide is as follows:

1) Use geological drilling technology to drill holes on the landslide 13 to be monitored. The holes must pass through all potential sliding surfaces 15 and extend to 3-5m below the bedrock surface; In the process of drilling less than 1°, the full casing protection wall is required except for the bedrock hole;

2) Before lowering the inclinometer pipe 1, clean the hole in the borehole until the mud water turns into clear water to ensure the smoothness of the borehole and the smooth lowering of the inclinometer pipe 1; after lifting the drill, immediately lower the drill hole with the sensor pasted on it The inclinometer tube 1;

3) Paste a fiber grating strain gauge on the outer wall of the first inclinometer tube 1, and cut a groove on the outer wall of the inclinometer tube 1, and fix the connecting optical fiber in the groove with adhesive tape; in order to verify the monitoring results of this device, put The optical fiber grating sensor group is pasted in a certain plane where the cross guide groove on the inner wall of the inclinometer 1 is located, so that the deformation monitored by the optical fiber grating is consistent with the deformation measured by the inclinometer;

4) After all the inclinometer tubes 1 are lowered into the holes, adjust the direction of the guide groove so that the direction of the guide groove and the direction of the 16 groups of fiber grating strain sensors of the inclinometer tube are facing the displacement direction of the landslide body;

5) Inject M5 fine sand cement mortar into the gap between the bedrock and the inclinometer tube 1, and guide the mortar with the grouting tube, and start grouting when the grouting tube is down to 1m from the bottom of the hole; between the soil and the inclinometer tube 1 Backfill fine sand in the gap;

6) Make a concrete pier at the hole, and bury a steel sleeve in the pier to protect the signal connectors of the 16 groups of optical fiber grating strain sensors in the inclinometer tube; connect the optical fiber signal connectors to the optical cable 5, and lead the signal to the monitoring station through the optical cable 5 .

Fig. 5 is a comparison diagram of the monitoring results of the fiber grating deep displacement monitoring system of the present invention and the monitoring results of the movable borehole inclinometer. The conditions for comparative monitoring are: the depth of the landslide is 29m, the underlying bedrock is covered, the bottom of the inclinometer tube 1 is buried in the bedrock 3m, the outer diameter of the inclinometer tube 1 is 70mm, the inner diameter is 60mm, and the 2.5m, 7.5m outside the inclinometer tube 1 m, 12.5m, 17.5m, 21.5m, and 30m respectively arrange a fiber grating sensor; the movable borehole inclinometer adopts a well-known imported brand, which has a long monitoring history in the field of borehole inclinometer and has good stability .

The composition of the thrust monitoring device of the landslide to the pipeline is as shown in Figure 6. It is an earth pressure box for monitoring the thrust of the pipeline 14 by the landslide. The input and the output of the grating demodulator are connected to the on-site host computer 8 . And the fiber grating sensor of landslide 13 to pipeline 14 thrust monitoring adopts fiber grating package earth pressure box fiber grating sensor 4; 4. The sensitive surface that feels the pressure faces the sliding direction of the landslide 13. In this way, the pressure measured by the earth pressure and fiber grating sensor 3 is the frontal thrust of the landslide 13 on the pipeline 14 .

The composition of the landslide thrust monitoring device for the pipeline, the soil pressure box fiber Bragg grating sensor 4 is shown in Figure 6, the soil pressure box fiber Bragg grating sensor 4 is fixed on the pipeline 14 through the earth pressure box bracket 21, and the earth pressure box fiber Bragg grating sensor 4 feels the pressure The sensitive surface faces the sliding direction of the landslide 13. In this way, the pressure measured by the earth pressure and fiber grating sensor 4 is the frontal thrust of the landslide 13 on the pipeline 14 . The earth pressure cell support 21 is composed of two arc-shaped steel plate clamps, one of which is welded with a base, and the fiber grating sensor 4 of the earth pressure cell is embedded in the base, and a certain margin is maintained so that the earth pressure cell can Transform freely. The clip connectors 23 at both ends of the earth pressure cell support 21 are connected by nuts. When the landslide 13 slides, the thrust of the landslide 13 to the earth pressure cell can be measured by the earth pressure cell fiber grating sensor 4, and the soil body self-weight pressure that the earth pressure cell fiber grating sensor 4 bears is subtracted from the measured value, which is the deformation of the landslide 13. Thrust generated by pipeline 14.

As shown in Figure 7 and Figure 8, the monitoring device for pipe body stress is to arrange a pipe monitoring section at the edge of both sides of the landslide and the center of the landslide, and arrange 3 pipe bodies evenly around the periphery of each monitoring section of the pipe 14 The fiber grating sensor 3 and the three tube fiber grating sensors 3 are arranged on a plane perpendicular to the axis of the pipeline 14 . The output of the tube fiber grating sensor 3 is connected to the input of the optical switch 6, the output of the optical switch 6 is connected to the input of the fiber grating demodulator 7, and the output of the fiber grating demodulator 7 is connected to the on-site host computer 8.

The electrical principle of the single channel of the device is shown in Figure 4. The PC connector of the tube fiber grating sensor 3 is connected with the PC connector of the optical switch 6 with an optical fiber. The PC connector of the switch 6 is connected to the CH1 end of the fiber grating demodulator 7SM125, and the LAN port of the fiber grating demodulator 7SM125 is connected to the LAN port of the upper computer 8.

The composition of the monitoring device for pipe body stress is shown in Figure 7 and Figure 8. A pipeline monitoring section is arranged on both sides of the landslide and at the center of the landslide, and the distance between the monitoring sections should not exceed 60m. Three tube fiber grating sensors 3 are evenly arranged on the outer periphery of each monitoring section of the pipeline 14 and the three tube fiber grating sensors 3 are arranged on a plane perpendicular to the axis of the pipeline 14 . When installing the tube fiber grating sensor 3, scrape off the anticorrosion layer of the tube 14 completely, and polish the surface of the tube 14 until smooth, and paste the tube fiber grating sensor package 24 with the quick-drying adhesive 3 to package the tube fiber grating sensor 3. After the three tube fiber grating sensors 3 are all pasted, lead the lead fibers of the tube fiber grating sensors 3 to the ground and protect them.

When the pipeline 14 is axially subjected to tensile/compressive stress, the three pipe fiber grating sensors 3 are subjected to tensile/compressive strain; according to a certain algorithm, the maximum strain on the section of the pipeline 14 can be calculated from the three strains in the section. size and position. Based on the elastic theory of steel, the maximum tensile/compressive stress on the section of the pipe 14 can be obtained. The selection of the monitoring section is very important to the monitoring effect.

A large number of studies have shown that the key performance of the stress of the landslide 13 on the pipeline 14 is in the axial direction, and the measurement of the axial stress of the pipeline 14 can better determine the acceptable stress state of the pipeline 14. Therefore, the tube fiber grating sensor 3 only measures the axial strain of the tube 14 .

The on-site monitoring station is set up at the landslide site, including optical fiber junction box, connecting optical cable 5, optical switch 6, fiber grating demodulator 7, host computer 8, GPRS transmission module 9; the optical fiber junction box and connecting optical cable of each fiber grating sensor 5 Connect the fiber grating sensors at various positions on the landslide 13 to the optical switch 6 of the monitoring station, the output of the optical switch 6 is connected to the fiber grating demodulator 7, the output of the fiber grating demodulator 7 is connected to the host computer 8, and the output of the host computer 8 Connect GPRS transmission module 9. The optical fiber junction box and connecting optical cable 5 of each optical fiber grating sensor centrally transmit the optical fiber grating sensor signals at various positions on the landslide 13 to the optical switch 6 of the monitoring station, and the optical switch 6 sequentially converts the signals of each channel to the optical fiber grating demodulator 7. The fiber grating demodulator 7 demodulates the central wavelength displacement of each fiber grating sensor to the host computer 8, and the host computer 8 automatically calculates each monitoring value and sends it to the GPRS transmission module 9 and receives the signal of the GPRS transmission module 9 for control The GPRS transmission module 9 transmits the monitoring quantities calculated by the upper computer 8 to the receiving terminal located in the office through the public wireless communication network, and can also accept the signal of the receiving terminal and send it to the lower computer 11.

in:

Optical switch: choose Guanglong Technology SUM-FSW;

Fiber Bragg grating demodulator: select SM125;

Host computer and program: Advantech IPC-610 is selected, and the program is self-edited;

GPRS transmission module: Siemens MC35i.

The receiving terminal located in the office includes the following 2 parts:

(1) GPRS receiving module 10, for receiving the monitoring amount that the on-site monitoring station GPRS transmission module 9 sends, and transmit to terminal lower computer 11, also can send feedback instruction to on-site GPRS transmission module 9;

(2) lower computer 11 and program are used to download the signal of terminal GPRS receiving module 10, and call program to carry out automatic analysis, analysis result is compared with warning threshold value, implements reporting to the police when necessary;

(3) Alarm device 12, used for generating an audible warning signal when the analysis result exceeds the alarm threshold; the alarm device 12 is controlled by the lower computer 11 and the program.

The working principle of the system is as follows: when the landslide 13 slides, the inclinometer tube 1 buried in the deep part of the landslide 13 is subjected to bending strain due to the thrust of the landslide 13 soil, and the inclinometer tube fiber grating sensor 16 on the inclinometer tube 1 senses To the tensile strain, the horizontal displacement on the inclinometer tube can be obtained by calculation, that is, the horizontal displacement of the deep part of the landslide 13; by connecting the optical cable 5, the sensor signal is transmitted to the optical switch 6, and the optical switch 6 converts the signal to the fiber grating The demodulator 7, the optical fiber grating demodulator 7 demodulates the center wavelength displacement of the sensor wavelength and sends it to the host computer 8, and the host computer 8 automatically calculates the center wavelength displacement demodulated by the demodulator as the monitoring amount, and The monitoring quantity is sent to the on-site GPRS transmission module 9, and the GPRS transmission module 9 transmits the signal to the terminal GPRS receiving module 10 through the public wireless communication network, and the terminal GPRS receiving module 10 sends to the terminal lower computer 11, and the terminal lower computer 11 transmits each monitoring quantity Compared with the alarm threshold, an alarm is given when necessary.

in:

GPRS receiving module 10: choose Siemens MC35i;

Lower computer 11 and program: Advantech IPC-610 is selected as the lower computer; the program is self-edited.

Alarm 12: choose Bosch DS-7400.

When monitoring the system constructed by the above method, if the landslide 13 slides, the inclinometer pipe 1 buried in the deep part of the landslide 13 is subjected to bending strain due to the thrust of the landslide 13 soil, and the inclinometer pipe fiber grating sensor 16 on the inclinometer pipe 1 Feeling the tensile strain, the horizontal displacement on the inclinometer pipe 1 can be obtained through calculation, that is, the horizontal displacement in the deep part of the landslide 13; thus, the stress on the pipeline 14 can be measured.

After long-term monitoring, this example has accurate positioning and high spatial resolution; it is easy to build a monitoring system, and it is easy to realize real-time automatic collection, analysis and remote release of pipeline landslide 13 monitoring data, and remote real-time automatic alarm. It avoids tedious manual data collection and reduces the alarm time, which is very important for the adoption of pipeline emergency measures.

Claims (6)

1. A fiber grating-based pipeline landslide deep displacement monitoring and early warning system is characterized in that it is composed of a landslide deep displacement monitoring device, a landslide thrust monitoring device for pipelines, a pipeline strain monitoring device, an on-site monitoring station, and a receiving terminal in an office; The inclinometer tube strain fiber grating sensor (16) of the on-site landslide deep displacement monitoring device installed in the landslide in a certain structure, the earth pressure cell strain fiber grating sensor (4) of the landslide thrust monitoring device for the pipeline and the pipeline strain monitoring device The output of the tube strain fiber grating sensor (3) is connected to the automatic optical switch (6) of the on-site monitoring station, the output of the automatic optical switch (6) is connected to the input of the fiber grating demodulator (7), and the host computer (8) One end output of one end connects the one end input of automatic optical transfer switch (6); The output of fiber grating demodulator (7) also connects the input of host computer (8); The output of host computer (8) connects GPRS transmission module (9), The receiving terminal GPRS receiving module (10) of the office is connected to the input of the lower computer (11), and the output of the lower computer (11) is connected to the alarm (12) and the display. 2. The pipeline landslide deep displacement monitoring and early warning system based on fiber grating according to claim 1, is characterized in that the electrical principle of the system is: Three FBG sensors for monitoring the deep displacement of the landslide, the thrust of the landslide on the pipeline and the strain of the pipeline respectively--Fiber Bragg Grating Sensor for Inclinometer Tube (16), Fiber Bragg Grating Sensor for Earth Pressure Cell (4), and Fiber Bragg Grating Sensor for Pipe Body (3) The (PC) connector of the optical switch (6) is connected with the (PC) connector of the optical switch (6) with an optical fiber, and the (R232) of the optical switch (6) is directly connected to the (R232) of the upper computer (8), and the (R232) of the optical switch (6) The (PC) connector is connected to the (CH1) end of the fiber grating demodulator (7) SM125, the (LAN) port of the fiber grating demodulator (7) SM125 is connected to the (LAN) port of the host computer (8), and the host computer (8) )’s (R232) port is connected to the (R232) port of the GPRS transmission module (9) Siemens MC35i, and the GPRS transmission module (9) passes through the antenna GSM and GPRS network, and is connected by (R232) after being received by the GPRS receiving module (10) antenna GSM To the (R232) of the lower computer (11), the output of the lower computer (11) is connected to the (R232) of the alarm (12) DS-7400 by (R232), and the output of the lower computer (11) is connected to the display by (VGA) (VGA) terminal; The output signals of the three types of fiber grating sensors that monitor the deep displacement of the landslide, the thrust of the landslide on the pipeline and the strain of the pipeline are conducted to the fiber grating demodulator (7) one by one, and the fiber grating demodulator (7) demodulates each fiber grating The central wavelength displacement of the sensor is sent to the host computer (8), and the cycle of the optical switch (6) conducting the signal to the fiber grating demodulator (7) is controlled by the host computer (8); the host computer (8) automatically calculates Each monitoring quantity loses to GPRS transmission module (9) and accepts the signal of GPRS transmission module (9) to control, and GPRS transmission module (9) transmits each monitoring quantity calculated by host computer (8) to be located in office through public wireless communication network The receiving terminal GPRS receiving module (10) can also accept the signal of the receiving terminal, and after sending to the lower computer (11) to process, it is displayed by the display and reported to the police by the alarm (12). 3. The pipeline landslide deep displacement monitoring and early warning system based on fiber gratings according to claim 1, characterized in that the installation structure of the landslide deep displacement monitoring device inclinometer tube fiber grating sensor (16) in the landslide is as follows: 1) On the landslide (13) to be monitored, there are holes that pass through all potential sliding surfaces (15) and extend to 3-5m below the bedrock surface. The hole diameter is Φ110mm, the hole inclination is less than 1° and the bedrock is removed There are casing protection walls outside the hole; 2) On the outer wall of the first inclinometer tube (1), there is a groove for fixedly connecting the optical fiber and a fiber grating strain gauge is pasted; the fiber grating sensor group is pasted on a certain plane where the cross guide groove on the inner wall of the inclinometer tube (1) is located Inside; 3) All the inclinometer tubes (1) are placed in the holes, and the direction of the guide groove and the direction of the optical fiber grating sensor (16) group of the inclinometer tubes are towards the displacement direction of the landslide body; 4) There is M5 fine sand cement mortar in the gap between the bedrock and the inclinometer tube (1); there is fine sand in the gap between the soil and the inclinometer tube (1); 5) The hole is a concrete pier, and there is a steel sleeve inside the pier; the optical fiber signal connector is connected with the optical cable (5), and the optical cable (5) is connected to the monitoring station. 4. The pipeline landslide deep displacement monitoring and early warning system based on optical fiber grating according to claim 3, is characterized in that described inclinometer pipe optical fiber grating sensor (16) is divided into measuring axial strain and measuring two kinds of temperature; The inclinometer fiber Bragg grating sensor (16) of the strain is pasted on the outer wall of the inclinometer tube (1) with quick-drying glue, and the inclinometer fiber Bragg grating sensor (16) is sealed with foam sealant; the temperature measuring inclinometer fiber Bragg grating sensor (16) Place it freely at a certain distance on the inclinometer tube (1), and perform temperature compensation on the group of fiber grating strain sensors (16) in the inclinometer tube. 5. The pipeline landslide deep displacement monitoring and early warning system based on fiber grating according to claim 1, characterized in that the landslide to pipeline thrust monitoring device earth pressure box fiber grating sensor (4) is composed of: earth pressure box fiber optic The grating sensor (4) is fixed on the pipeline (14) through the earth pressure cell support (21), and the sensitive surface of the earth pressure cell fiber grating sensor (4) to feel the pressure faces the sliding direction of the landslide (13); the earth pressure cell support (21 ) is composed of two arc-shaped steel plate clamps, one of which is welded with a base, and the fiber grating sensor (4) of the earth pressure cell is embedded in the base, and a certain margin is maintained so that the earth pressure cell can be deformed freely ; The clip connectors (23) at the two ends of the earth pressure box support (21) are connected by nuts. 6. The pipeline landslide deep displacement monitoring and early warning system based on fiber grating according to claim 1, characterized in that the pipe fiber grating sensor (3) of the pipeline strain monitoring device is composed of: on both sides of the landslide and A pipeline monitoring section is arranged at the center of the landslide, and the distance between the monitoring sections does not exceed 60m; 3 pipe fiber grating sensors (3) are evenly arranged on the periphery of each monitoring section and 3 pipe fiber grating sensors (3) Arranged on a plane perpendicular to the axis of the pipeline (14); the tube fiber grating sensor (3) is installed on the smooth surface of the pipeline (14), and the tube fiber grating sensor package (24) is pasted with quick-drying glue, and the tube fiber grating sensor (3) is packaged. The body fiber grating sensor (3); the lead fiber of the tube body fiber grating sensor (3) is led to the ground together and protected.

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