CN111609808A - Deformation monitoring system for oil-gas pipeline of water-sealed tunnel - Google Patents
Deformation monitoring system for oil-gas pipeline of water-sealed tunnel Download PDFInfo
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- CN111609808A CN111609808A CN202010615402.8A CN202010615402A CN111609808A CN 111609808 A CN111609808 A CN 111609808A CN 202010615402 A CN202010615402 A CN 202010615402A CN 111609808 A CN111609808 A CN 111609808A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/16—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
- G01B11/18—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge using photoelastic elements
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
- G01L5/16—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring several components of force
- G01L5/166—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring several components of force using photoelectric means
Abstract
The invention discloses a water-sealed tunnel oil-gas pipeline deformation monitoring system which comprises a pipeline deformation monitoring subsystem arranged in a tunnel, a data acquisition and transmission subsystem outside the tunnel and a monitoring and early warning subsystem positioned in a monitoring and early warning center. The pipeline deformation monitoring subsystem comprises a pipeline macroscopic deformation monitoring device and a pipeline microscopic deformation monitoring device. The pipeline macroscopic deformation monitoring device is arranged at the obvious position of the pipeline displacement, is installed close to the pipeline macroscopic deformation monitoring device, and comprehensively analyzes the deformation and stress state of the pipeline. The invention reasonably arranges the monitoring cross section by taking the key and dangerous positions as the principle, has more scientific and reasonable monitoring layout and outstanding economy, carries out real-time analysis and calculation and early warning information release according to the monitoring result, takes precautionary measures in time and is beneficial to ensuring the operation safety of the pipeline. In addition, the monitoring system has no requirement on the operation condition of the pipeline during installation, does not need to reduce the pressure and does not influence the normal operation of the oil and gas pipeline.
Description
Technical Field
The invention relates to the technical field of oil and gas pipeline deformation monitoring, in particular to a deformation monitoring system for an oil and gas pipeline of a water-sealed tunnel.
Background
River crossing is a key project in the construction of long oil and gas pipelines. In recent years, the oil and gas pipelines are widely laid in a shield crossing mode when crossing large and medium rivers. The tunnel crossing is divided into a water-sealed tunnel and a non-water-sealed tunnel, and the tunnel with poor water-sealing property and obvious water seepage on the tunnel wall is usually in a water-sealed mode.
Different from buried pipelines, the tunnel crossing section pipeline has obvious ascending and descending sections in structural design for adapting to the terrain of a tunnel, a larger elbow angle exists at a corner, the constraint of the pipeline in the tunnel is limited, the elbow generates unbalanced action under the action of internal pressure, the elbow is easy to deform, and the damage of an adjacent pipe clamp and larger pipeline displacement can be caused. Especially in water-sealed tunnels, the external pressure and buoyancy effect of water on the pipeline can cause the pipeline to deform and displace due to the fact that the water depth is deeper. The water seal tunnel is operated in a water injection sealing mode under the common condition, personnel cannot enter the tunnel, and the state of the pipeline can be checked only through regular overhaul. Before the water seal tunnel is overhauled, personnel can enter a limited space to carry out pipeline safety inspection after water pumping, draining and full ventilation, the engineering quantity is large, the operation period is long, the cost is high, and the change of water pressure and buoyancy before and after overhauling easily causes the stress change of the pipeline, so that the operation safety of the pipeline is possibly threatened.
From the result of several water seal tunnel periodic inspection in recent years, the pipeline receives moment of flexure, axial tension and external pressure combined action, easily produces great load combination in tunnel turning department, leads to the obvious displacement of local pipeline, and the anchor bolt that is used for fixed pipeline originally seriously warp, and the anchor bolt of pipe strap is cracked even, seriously influences the normal operating of pipeline. Because the displacement and the deformation state of the pipeline at the moment of inspection can only be obtained during each pipeline overhaul, the in-place state of the pipeline cannot be mastered during the operation process, and especially under the working conditions of tunnel water injection, water pumping, pressure regulation, tunnel displacement and the like, the safety condition of the pipeline cannot be obtained in real time, and great uncertainty and risk exist. Once the stress of the pipeline exceeds the strength of the pipeline material, accidents such as pipeline leakage and deflagration can be caused, and the risk potential is huge. The tunnel inner pipeline belongs to a high-risk pipeline section and is focused on. The water-sealed tunnel oil-gas pipeline real-time monitoring is carried out, the on-site state and the stress condition of the pipeline can be mastered by monitoring the macroscopic deformation and the microscopic deformation of the pipeline, and early warning information is timely issued when abnormality is found, so that pipeline safety accidents are prevented.
Disclosure of Invention
In order to realize pipeline deformation monitoring in the water-sealed tunnel, the invention provides a monitoring system for measuring macroscopic deformation and microscopic deformation of a pipeline in a water-sealed environment.
In order to solve the technical problems, the invention provides the following technical scheme:
a water-sealed tunnel oil-gas pipeline deformation monitoring system comprises a pipeline deformation monitoring subsystem arranged in a tunnel, a data acquisition and transmission subsystem arranged outside the tunnel, and a monitoring and early warning subsystem positioned in a monitoring and early warning center; the pipeline deformation monitoring subsystem comprises a pipeline macroscopic deformation monitoring device and a pipeline microscopic deformation monitoring device; the data acquisition and transmission subsystem comprises an optical fiber terminal box, an optical fiber grating demodulator, a data transmission module, a lightning arrester and a power supply device, and the monitoring and early warning subsystem is positioned at a monitoring and early warning center entity server or a cloud server end; the pipeline intrinsic safety monitoring and early warning system comprises a data center for receiving monitoring data and screening data, a data analysis module for carrying out pipeline displacement analysis and pipeline strain/stress analysis, and a monitoring and early warning module for integrating the macroscopic displacement deformation and the stress state of a pipeline, taking pipeline intrinsic safety monitoring and early warning as a core and issuing corresponding early warning information according to the calculated ratio of the maximum value of the axial additional tensile stress and the maximum value of the compressive stress of the pipeline to the allowable value of the axial additional tensile stress and the compressive stress of the pipeline.
In the deformation monitoring system for the oil and gas pipeline in the water-sealed tunnel, the pipeline macroscopic deformation monitoring device comprises a specially-made stainless steel pipe hoop, a pipe hoop fixing bolt, an upper adjusting plate, a fiber grating displacement meter connecting rod, a fiber grating displacement meter, a lower adjusting plate and a ground fixing bolt; the special stainless steel pipe hoop is divided into two semicircles and is fastened on the surface of the pipeline through a pipe hoop fixing bolt; in order to prevent the special stainless steel pipe hoop from damaging the pipeline and the three PE anticorrosive layers, a rubber plate with the thickness of 6mm is arranged between the pipeline and the stainless steel pipe hoop; connecting an upper adjusting plate with a special stainless steel pipe hoop through a pipe hoop fixing bolt on one side close to the tunnel step; the lower adjusting plate is fixed on the tunnel ground through a ground fixing bolt, and the central lines of the upper adjusting plate and the lower adjusting plate are ensured to be overlapped in the vertical direction during installation; and a fiber grating displacement meter is arranged between the upper adjusting plate and the lower adjusting plate, and connecting rods at two ends of the grating displacement meter are fastened in clamping holes of the upper adjusting plate and the lower adjusting plate.
In the deformation monitoring system for the oil and gas pipeline in the water-sealed tunnel, the pipeline microscopic deformation monitoring device comprises a fiber bragg grating strain gauge, a fiber bragg grating thermometer, a monitoring cross section protection layer, a single-core armored optical cable, an optical cable protection pipe, a tunnel optical cable and a tunnel optical cable splicing box; the fiber grating strain gauge and the fiber grating thermometer are both arranged on the surface of the pipeline steel body, three PE anti-corrosion layers of the pipeline need to be opened locally during installation, and the fiber grating strain gauge and the fiber grating thermometer are welded on the surface of the pipeline by using a spot welding technology.
In the water-seal tunnel oil and gas pipeline deformation monitoring system, the pipeline macroscopic deformation monitoring device leads out the optical cable and is adjacent to the pipeline microscopic deformation monitoring device, after the optical cable is connected in series at the top of the pipeline, the head and the tail ends of the series optical cable are welded with the tunnel optical cable through the optical cable splice closure by using 2 paths of single-core armored optical cables, the single-core armored optical cables are protected by using the optical cable protection tubes, and sealant is poured into the optical cable splice closure to prevent water from permeating.
In the deformation monitoring system for the oil-gas pipeline in the water-sealed tunnel, a standby channel is designed when the single-core armored optical cable is connected into the tunnel optical cable, when a fault occurs at a certain position of a serial optical cable consisting of the pipeline macroscopic deformation monitoring device and the pipeline microscopic deformation monitoring device, partial sensor data is measured in a forward direction by one end, and residual sensor data is measured in a reverse direction by the other end, so that the normal reading of all sensor data is ensured.
In the deformation monitoring system for the oil and gas pipeline in the water-sealed tunnel, the optical fiber terminal box in the data acquisition and transmission subsystem is used for separating each optical cable in the tunnel optical cable, is convenient to connect with each optical cable by using a jumper wire and respectively reads monitoring data of each optical cable; the fiber grating demodulator is connected with each optical cable through a jumper wire, regularly transmits laser with single wavelength to each optical cable, the transmitted laser can change in a larger wave band range, and simultaneously records the return wavelength of the sensor in each optical cable and stores the return wavelength in the fiber grating demodulator; the data transmission module is used for transmitting the monitoring data stored in the fiber grating demodulator to a data center of a monitoring and early warning subsystem of a designated server side; the lightning arrester is used for preventing the integrated field monitoring station in the open field environment from being damaged by field equipment and lines due to lightning; and the power supply device is used for supplying power to the grating demodulator and the data transmission module and ensuring that the equipment normally works for 24 hours.
In the deformation monitoring system for the oil and gas pipeline in the water-sealed tunnel, the monitoring and early warning subsystem and the data center receive monitoring data and perform data screening, and the data screening is divided into two sub-steps of effective data screening and abnormal data screening; issuing data acquisition commands for m times when data are acquired each time, and acquiring n groups of data successfully, then performing effective data screening and abnormal data screening on the n groups of data in sequence; the effective data screening is to primarily screen the n groups of data according to the range of the sensor, eliminate the ineffective data beyond the range of the sensor, and leave n2Group data; the abnormal data is screened for the remaining n according to the Grabbs test method2Group dataThe detection level was taken to be 5%, and the critical value Gp (n) of the Grabbs test was defined2) And calculating the remainder n in turn2Mean of group data
Standard deviation of
And the Grabbs test statistic for each group number
Selecting the remaining n2Maximum value of the Grabbs test statistic G in group datak(Gk＝max(Gi) Is analyzed if G is presentk＞Gp(n2) The k data is an abnormal value, the k data needs to be removed, and the rest n2＝n21 group of data is subjected to the abnormal data screening process again until Gk＜Gp(n2) If the residual data are not abnormal values, the residual data are reserved, the average value of the residual data is taken as the monitoring data after the screening of the current measurement result value, and the data screening is ended;
the screened monitoring data enter a data analysis module to carry out pipeline displacement analysis and pipeline strain/stress analysis; the pipeline displacement is directly calculated by using monitoring data according to a wavelength and displacement calculation formula under the premise of considering the temperature wavelength; the pipeline strain value of any position of the monitoring section can be obtained by calculation after eliminating the influence of temperature according to 3 groups of strain data on the monitoring section at the same moment, and the specific calculation steps are as follows:
the pipeline strain consists of film strain, y-direction bending strain and z-direction bending strain; the strain of the film at the monitored section, the maximum y-direction bending strain and the maximum z-direction bending strain are respectively set asm、
According to the superposition principle, the strain at any point on the section of the pipeline is obtained as shown in formula 1:
the monitoring strain values of the top and the left and the right sides of the pipeline are respectively U (0, r)o)、
It andm、
the relationship of (a) to (b) is as follows:
equation 2:
equation 3:
equation 4:
the monitored cross-sectional film strain and the maximum y-direction and z-direction bending expressed by the monitored strain are obtained from equations 2-4, respectively:
equation 5:
equation 6:
equation 7:
the maximum bending strain of the cross section can be obtained by combining the bending strains in the y and z directions, and the formula 8:
the angle at which the maximum bending strain is, equation 9:
accordingly, monitoring the cross-sectional maximum and minimum axial strain, equation 10:
axial strain at any point of the pipe section represented by the monitored strain, equation 11:
also, from the above equation, the maximum axial strain at each angle of the monitored cross section can be obtained, equation 12:
monitoring the cross-sectional average axial strain, equation 13:
monitoring the cross-sectional bending strain, equation 14:
obtaining maximum axial stress, average axial stress and bending stress values of each angle of the monitored section according to a pipeline stress-strain relation curve by a formula 12-a formula 14;
a monitoring and early warning module in the monitoring and early warning subsystem integrates the macroscopic displacement deformation and the stress state of the pipeline and issues early warning information by taking the intrinsic safety monitoring and early warning of the pipeline as a core; when the axial additional tensile and compressive stress values of the pipeline reach or exceed 30% of the axial additional tensile and compressive stress allowable values, blue early warning information is issued; when the axial additional tensile and compressive stress values of the pipeline reach or exceed 60% of the axial additional tensile and compressive stress allowable values, yellow early warning information is issued; and when the axial additional tensile and compressive stress values of the pipeline reach or exceed 90% of the axial additional tensile and compressive stress allowable values, red early warning information is issued.
Compared with the prior art, the invention has the following beneficial effects: the displacement sensor and the strain sensor are passive sensors, are waterproof and water pressure resistant, can be used for underwater long-term monitoring, are particularly suitable for monitoring macroscopic and microscopic deformation of the oil-gas pipeline in the water-sealed tunnel, do not have adverse effect on the underwater pipeline, can realize real-time online monitoring of the running process of the pipeline, are also suitable for monitoring deformation of the pipeline in the non-water-sealed tunnel, can be replaced by a vibrating wire sensor according to actual needs without adjusting the existing monitoring mode, and have wider application range. The invention reasonably arranges the monitoring cross section by taking the control key and the dangerous part as the principle, and has more scientific and reasonable monitoring layout and outstanding economical efficiency. The monitoring and early warning system carries out real-time analysis and resolving and early warning information issuing according to the monitoring result, takes precautionary measures in time and is beneficial to ensuring the operation safety of the pipeline. In addition, the monitoring system has no requirement on the operation condition of the pipeline during installation, does not need to reduce the pressure and does not influence the normal operation of the oil and gas pipeline.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
fig. 1 is a schematic view of the overall structure of the pipe deformation monitoring system of the present invention.
Fig. 2 is a schematic view of the device for monitoring macroscopic deformation of the pipeline.
FIG. 3 is a schematic view of the pipe micro-deformation monitoring device of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example one
In order to monitor the deformation of an oil and gas pipeline at a tunnel crossing section, in particular to a water-sealed tunnel crossing section, the embodiment of the invention provides a deformation monitoring system for the oil and gas pipeline of the water-sealed tunnel, which is suitable for monitoring the deformation of the pipeline at the non-water-sealed tunnel crossing section, and the specific technical scheme is as follows:
as shown in fig. 1, a water-sealed tunnel oil-gas pipeline deformation monitoring system comprises a pipeline deformation monitoring subsystem arranged in a tunnel, a data acquisition and transmission subsystem arranged outside the tunnel, and a monitoring and early warning subsystem located in a monitoring and early warning center.
The pipeline deformation monitoring subsystem comprises a pipeline macroscopic deformation monitoring device and a pipeline microscopic deformation monitoring device. Before monitoring is carried out, a current pipeline three-dimensional walking pattern under a local coordinate system needs to be established according to a field pipeline centerline three-dimensional measurement result, and a pipeline three-dimensional walking pattern when completion is established under the same local coordinate system by combining a pipeline completion drawing; establishing a three-dimensional analysis model of completion time and the current pipeline by using a finite element method; converting the pipe constraints at different positions in the tunnel into corresponding constraint conditions by combining with the field investigation condition, loading the constraint conditions on a completed pipe three-dimensional analysis model, simultaneously applying internal pressure, external pressure and local load on the pipe, and repeatedly performing trial calculation to obtain the deformation state and the stress state of the pipe when the pipe configuration is changed into the current pipe configuration when the pipe configuration is completed; and selecting the positions with obvious deformation and concentrated stress according to the analysis result to monitor the macroscopic deformation and the microscopic deformation of the pipeline. As shown in fig. 2, when the pipeline macroscopic deformation monitoring device is applied, a position where the displacement deformation of the pipeline is obvious is selected for installation, the pipeline microscopic deformation monitoring device is installed close to the pipeline macroscopic deformation monitoring device or a position where the stress of the pipeline is concentrated is selected for installation, and the deformation and the stress state of the pipeline are comprehensively monitored. The device for monitoring the macroscopic deformation of the pipeline comprises a specially-made stainless steel pipe hoop 101, a pipe hoop fixing bolt 105, an upper adjusting plate 106, a fiber grating displacement meter connecting rod 110, a fiber grating displacement meter 107, a lower adjusting plate 108 and a ground fixing bolt 109. The special stainless steel pipe clamp 101 is divided into two semicircles and is fastened on the surface of a pipeline through a pipe clamp fixing bolt 105; in order to prevent the special stainless steel pipe clamp 101 from damaging the pipe 104 and the three-layer PE anticorrosive layer 103, a 6mm thick rubber plate 102 is installed between the pipe 104 and the stainless steel pipe clamp 101. On the side near the tunnel step 113, the upper regulating plate 106 is connected to the special stainless steel pipe clamp 101 by a pipe clamp fixing bolt 105. The lower adjusting plate 108 is fixed on the tunnel ground by a ground fixing bolt 109, and the central lines of the upper and lower adjusting plates are ensured to be overlapped in the vertical direction during installation. A fiber grating displacement meter 107 is arranged between the upper adjusting plate 106 and the lower adjusting plate 108, and connecting rods 110 at two ends of the grating displacement meter are fastened in clamping holes of the upper adjusting plate and the lower adjusting plate. Different clamping hole positions are arranged on the upper and lower adjusting plates, and the installation position can be adjusted according to the actual distance between the pipeline and the ground and the actual length of the sensor and the connecting rod. As shown in FIG. 3, the pipeline micro-deformation monitoring device comprises a fiber grating strain gauge 201, a fiber grating thermometer 202, a monitoring section protective layer 203, a single-core armored cable 204, a cable protective tube 205, a tunnel cable 111 and a tunnel cable splice box 206, wherein at least 3 sets of the fiber grating strain gauges 201 and 1 set of the fiber grating thermometer 202 are installed at the possible pipeline stress concentration parts analyzed in the previous period. The fiber grating strain gauge 201 and the fiber grating thermometer 202 need to be installed on the surface of a pipeline steel body, three PE corrosion-resistant layers 103 of the pipeline need to be opened locally during installation, and the fiber grating strain gauge 201 and the fiber grating thermometer 202 are welded on the surface of the pipeline by using a spot welding technology. In order to accelerate the on-site construction progress, the fiber grating strain sensor and the fiber grating temperature sensor which are used on the same section can be customized in advance and are connected in parallel. And then, drying and viscoelastic body corrosion prevention are carried out on the local opening position of the three PE corrosion-resistant layers 103, so that water vapor is prevented from remaining and corroding the pipeline and the sensor. And after the corrosion prevention is finished, an electric spark leak detector is needed to ensure complete corrosion prevention. The fiber grating strain gauge 201 and the fiber grating thermometer 202 lead out the optical cable, and the optical cable needs to be wound on the pipe wall in an S shape, enough deformation is reserved, the pipeline is prevented from being deformed and dragging the cable to cause damage to the optical cable, and the whole monitoring section is protected by the monitoring section protection layer 203.
After the optical cable led out by the pipeline macroscopic deformation monitoring device and the optical cable led out by the adjacent pipeline microscopic deformation monitoring device are connected in series at the top of the pipeline, the head end and the tail end of the optical cable connected in series are welded with the tunnel optical cable 111 through the optical cable splice closure 206 by using the 2-path single-core armored optical cable 204, and sealant is poured into the optical cable splice closure 206 to prevent water from permeating. When the single-core armored optical cable 204 is connected into the tunnel optical cable, a standby channel is designed, when a fault occurs at a certain position of a serial optical cable consisting of the pipeline macroscopic deformation monitoring device and the pipeline microscopic deformation monitoring device, partial sensor data can be measured in a forward direction by one end, and the residual sensor data can be measured in a reverse direction by the other end, so that the normal reading of all the sensor data is ensured. The single-core armored cable 204 is externally penetrated by a PVC cable protection tube 205. The tunnel optical cable 111 is a standard loose tube layer stranded steel wire armored optical cable which is waterproof, resistant to water pressure, resistant to hydrolysis, good in corrosion resistance and high in strength, and can stably operate in an underwater environment for a long time. The tunnel optical cable is fixed in an optical cable box above a wall handrail 112 on one side of a tunnel inner step 113, and a certain length of cable is reserved in the laying process. And comprehensively determining the layout position of the data acquisition and transmission subsystem according to the actual condition of the tunnel, the installation number and the installation positions of the pipeline macroscopic deformation monitoring devices and the pipeline microscopic deformation monitoring devices. The tunnel optical cable is led out of the tunnel from one side or two sides of the tunnel and is connected to the data acquisition and transmission subsystem near the tunnel opening.
The data acquisition and transmission subsystem outside the tunnel comprises an optical fiber terminal box, an optical fiber grating demodulator, a data transmission module, a lightning arrester and a power supply device. If no commercial power is available on site, a solar cell panel and a storage battery power supply system can be equipped to ensure 24-hour online monitoring and timed data transmission of the monitoring equipment.
According to the setting, the optical fiber terminal box in the data acquisition and transmission subsystem is used for separating all optical cables in the main optical cable in the tunnel, so that the jumper wires are conveniently used for connecting all the optical cables, and all the monitoring data are respectively read. The fiber grating demodulator is connected with each optical cable through a jumper wire, and regularly transmits laser with single wavelength to each optical cable, the transmitted laser can change back and forth in a larger wave band range, and the return wavelength of the sensor in each optical cable is recorded and stored in the optical fiber terminal box. Lightning arrester is used for preventing open-air open environment under integration wildThe external monitoring station is affected by lightning to damage field equipment and lines. The data acquisition and transmission subsystem acquires monitoring data at regular time or in real time and transmits the data to a monitoring and early warning center entity server or a cloud server by using a wireless communication network through a data transmission module. The monitoring and early warning subsystem is positioned at a monitoring and early warning center entity server or a cloud server end and comprises a data center used for receiving monitoring data and performing data screening, a data analysis module used for carrying out pipeline displacement analysis and pipeline strain/stress analysis, and a monitoring and early warning module used for integrating pipeline macroscopic displacement deformation and pipeline stress state, taking pipeline intrinsic safety monitoring and early warning as a core and issuing corresponding early warning information according to the proportion of the maximum value of pipeline axial additional tensile stress and compressive stress in the allowable value of axial additional tensile stress and compressive stress obtained through calculation. Wherein, the data center needs to be subjected to data screening after receiving the monitoring data. The data screening is divided into two sub-steps of effective data screening and abnormal data screening. If m data acquisition commands are issued each time data is acquired, and n groups of data are successfully acquired, effective data screening and abnormal data screening are sequentially executed on the n groups of data. The effective data screening is to primarily screen the n groups of data according to the range of the sensor, eliminate the ineffective data beyond the range of the sensor, and leave n2Group data. The abnormal data is screened for the remaining n according to the Grabbs test method2The data acquisition detection level was 5% defining the critical value Gp (n) of the Grabbs test2) And calculating the remainder n in turn2Mean of group data
Standard deviation of
And the Grabbs test statistic for each group number
Selecting the remaining n2Maximum value of the Grabbs test statistic G in group datak(Gk＝max(Gi) Is analyzed if G is presentk＞Gp(n2) The k data is stated as being differentConstant value, need to eliminate the k data, for the rest n2＝n21 group of data is subjected to the abnormal data screening process again until Gk＜Gp(n2) And if the residual data are not abnormal values, the residual data are reserved, the average value of the residual data is taken as the monitoring data after the screening of the current measurement result value, and the data screening is ended.
The screened monitoring data can enter a data analysis module to carry out pipeline displacement analysis and pipeline strain/stress analysis. The pipeline displacement can be directly calculated by using monitoring data according to a wavelength and displacement calculation formula under the premise of considering the temperature wavelength. The pipeline strain/stress analysis is relatively complex, based on the assumption and superposition principle of a flat section in the elasticity theory, the pipeline strain value of any position of the monitoring section can be calculated according to 3 groups of strain data (3 groups of strain data and 1 group of temperature data when the fiber grating strain monitoring sensor is used) on the monitoring section at the same moment, and the specific calculation steps are as follows:
the pipe strain is composed of film strain, y-direction bending strain, and z-direction bending strain. The strain of the film at the monitored section, the maximum y-direction bending strain and the maximum z-direction bending strain are respectively set asm、
According to the superposition principle, the strain at any point on the section of the pipeline is obtained as shown in formula 1:
for the preferred axial strain sensor mounting method mentioned in the first embodiment, the monitored strain values at the top and left and right sides of the pipeline are respectively U (0, r)o)、
It andm、
the relationship of (a) to (b) is as follows:
equation 2:
equation 3:
equation 4:
from equations 2-4, the monitored cross-sectional film strain and the maximum y-direction and z-direction bending represented by the monitored strain are respectively:
equation 5:
equation 6:
equation 7:
the maximum bending strain of the cross section can be obtained by combining the bending strains in the y and z directions, and the formula 8:
the angle at which the maximum bending strain is, equation 9:
accordingly, monitoring the cross-sectional maximum and minimum axial strain, equation 10:
axial strain at any point of the pipe section represented by the monitored strain, equation 11:
also, from the above equation, the maximum axial strain at each angle of the monitored cross section can be obtained, equation 12:
monitoring the cross-sectional average axial strain, equation 13:
monitoring the cross-sectional bending strain, equation 14:
the maximum axial stress, the average axial stress and the bending stress value of each angle of the monitored section can be obtained according to the relation curve of the pipeline stress-strain by formulas 12 to 14.
A monitoring and early warning module in the monitoring and early warning subsystem integrates the macroscopic displacement deformation and the stress state of the pipeline and issues early warning information by taking the intrinsic safety monitoring and early warning of the pipeline as a core; when the axial additional tensile and compressive stress values of the pipeline reach or exceed 30% of the axial additional tensile and compressive stress allowable values, blue early warning information is issued; when the axial additional tensile and compressive stress values of the pipeline reach or exceed 60% of the axial additional tensile and compressive stress allowable values, yellow early warning information is issued; and when the axial additional tensile and compressive stress values of the pipeline reach or exceed 90% of the axial additional tensile and compressive stress allowable values, red early warning information is issued. The monitoring and early warning module of the monitoring and early warning subsystem integrates the macroscopic displacement deformation and the stress state of the pipeline, issues early warning information by taking intrinsic safety monitoring and early warning of the pipeline as a core, issues corresponding early warning information according to the proportion of the maximum axial additional tensile stress and the maximum axial additional tensile stress of the pipeline obtained by calculation to the allowable value of the axial additional tensile stress and the compressive stress, and automatically pushes the information to a mobile phone end of an appointed user in a short message mode, wherein the method specifically comprises the following steps:
when the axial additional tensile and compressive stress values of the pipeline reach or exceed 30% of the axial additional tensile and compressive stress allowable values, the monitoring and early warning subsystem issues blue early warning information;
when the axial additional tensile and compressive stress values of the pipeline reach or exceed 60% of the axial additional tensile and compressive stress allowable values, the monitoring and early warning subsystem issues yellow early warning information;
and when the axial additional tensile and compressive stress values of the pipeline reach or exceed 90% of the axial additional tensile and compressive stress allowable values, the monitoring and early warning subsystem issues red early warning information.
The displacement sensor and the strain sensor are passive sensors, are waterproof and water pressure resistant, can be used for underwater long-term monitoring, are particularly suitable for monitoring macroscopic and microscopic deformation of the oil-gas pipeline in the water-sealed tunnel, do not have adverse effect on the underwater pipeline, can realize real-time online monitoring of the running process of the pipeline, are also suitable for monitoring deformation of the pipeline in the non-water-sealed tunnel, can be replaced by a vibrating wire sensor according to actual needs without adjusting the existing monitoring mode, and have wider application range. According to the invention, the monitoring cross sections are reasonably arranged on the basis of controlling key and dangerous parts according to the on-site survey result, the pipeline completion drawing, the actually measured pipeline three-dimensional coordinates and the finite element analysis result, the monitoring layout is more scientific and reasonable, and the economy is outstanding. By monitoring macroscopic deformation and microscopic deformation of the pipeline, the in-place state and the stress condition of the pipeline are mastered in real time, and early warning information is issued in time when abnormality is found. The monitoring and early warning system carries out real-time analysis and resolving and early warning information issuing according to the monitoring result, takes precautionary measures in time and is beneficial to ensuring the operation safety of the pipeline. In addition, the monitoring system has no requirement on the operation condition of the pipeline during installation, does not need to reduce the pressure and does not influence the normal operation of the oil and gas pipeline.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (7)
1. A deformation monitoring system for an oil-gas pipeline of a water-sealed tunnel is characterized by comprising a pipeline deformation monitoring subsystem arranged in the tunnel, a data acquisition and transmission subsystem arranged outside the tunnel and a monitoring and early warning subsystem positioned in a monitoring and early warning center; the pipeline deformation monitoring subsystem comprises a pipeline macroscopic deformation monitoring device and a pipeline microscopic deformation monitoring device; the data acquisition and transmission subsystem comprises an optical fiber terminal box, an optical fiber grating demodulator, a data transmission module, a lightning arrester and a power supply device, and the monitoring and early warning subsystem is positioned at a monitoring and early warning center entity server or a cloud server end; the pipeline intrinsic safety monitoring and early warning system comprises a data center for receiving monitoring data and screening data, a data analysis module for carrying out pipeline displacement analysis and pipeline strain/stress analysis, and a monitoring and early warning module for integrating the macroscopic displacement deformation and the stress state of a pipeline, taking pipeline intrinsic safety monitoring and early warning as a core and issuing corresponding early warning information according to the calculated ratio of the maximum value of the axial additional tensile stress and the maximum value of the compressive stress of the pipeline to the allowable value of the axial additional tensile stress and the compressive stress of the pipeline.
2. The water-sealed tunnel oil and gas pipeline deformation monitoring system according to claim 1, wherein the pipeline macroscopic deformation monitoring device comprises a specially-made stainless steel pipe hoop, a pipe hoop fixing bolt, an upper adjusting plate, a fiber grating displacement meter connecting rod, a fiber grating displacement meter, a lower adjusting plate and a ground fixing bolt; the special stainless steel pipe hoop is divided into two semicircles and is fastened on the surface of the pipeline through a pipe hoop fixing bolt; in order to prevent the special stainless steel pipe hoop from damaging the pipeline and the three PE anticorrosive layers, a rubber plate with the thickness of 6mm is arranged between the pipeline and the stainless steel pipe hoop; connecting an upper adjusting plate with a special stainless steel pipe hoop through a pipe hoop fixing bolt on one side close to the tunnel step; the lower adjusting plate is fixed on the tunnel ground through a ground fixing bolt, and the central lines of the upper adjusting plate and the lower adjusting plate are ensured to be overlapped in the vertical direction during installation; and a fiber grating displacement meter is arranged between the upper adjusting plate and the lower adjusting plate, and connecting rods at two ends of the grating displacement meter are fastened in clamping holes of the upper adjusting plate and the lower adjusting plate.
3. The water-sealed tunnel oil and gas pipeline deformation monitoring system of claim 2, wherein the pipeline microscopic deformation monitoring device comprises a fiber grating strain gauge, a fiber grating thermometer, a monitoring section protection layer, a single-core armored optical cable, an optical cable protection tube, a tunnel optical cable and a tunnel optical cable splice closure; the fiber grating strain gauge and the fiber grating thermometer are both arranged on the surface of the pipeline steel body, three PE anti-corrosion layers of the pipeline need to be opened locally during installation, and the fiber grating strain gauge and the fiber grating thermometer are welded on the surface of the pipeline by using a spot welding technology.
4. The water-sealed tunnel oil and gas pipeline deformation monitoring system of claim 3, wherein after the optical cable led out from the pipeline macroscopic deformation monitoring device and the optical cable led out from the adjacent pipeline microscopic deformation monitoring device are connected in series at the top of the pipeline, the head and tail ends of the optical cable connected in series are welded with the tunnel optical cable through the optical cable splice closure by using 2-way single-core armored optical cable, the single-core armored optical cable is protected by using the optical cable protection tube, and the sealant is filled in the optical cable splice closure to prevent water from permeating.
5. The water-sealed tunnel oil and gas pipeline deformation monitoring system of claim 4, wherein a standby channel is designed when the single-core armored optical cable is connected to the tunnel optical cable, and when a fault occurs at a certain position of a serial optical cable composed of the pipeline macroscopic deformation monitoring device and the pipeline microscopic deformation monitoring device, partial sensor data is measured by one end in a forward direction, and the rest sensor data is measured by the other end in a reverse direction, so that the normal reading of all sensor data is ensured.
6. The water-sealed tunnel oil and gas pipeline deformation monitoring system according to claim 5, wherein the optical fiber termination box in the data acquisition and transmission subsystem is used for separating each optical cable in the tunnel optical cable, facilitating connection with each optical cable by using jumper wires, and reading monitoring data of each optical cable respectively; the fiber grating demodulator is connected with each optical cable through a jumper wire, regularly transmits laser with single wavelength to each optical cable, the transmitted laser can change in a larger wave band range, and simultaneously records the return wavelength of the sensor in each optical cable and stores the return wavelength in the fiber grating demodulator; the data transmission module is used for transmitting the monitoring data stored in the fiber grating demodulator to a data center of a monitoring and early warning subsystem of a designated server side; the lightning arrester is used for preventing the integrated field monitoring station in the open field environment from being damaged by field equipment and lines due to lightning; and the power supply device is used for supplying power to the grating demodulator and the data transmission module and ensuring that the equipment normally works for 24 hours.
7. The water-seal tunnel oil and gas pipeline deformation monitoring system of claim 6, wherein the monitoring and early warning subsystem and the data center receive monitoring data and screening data, and the data screening is divided into two sub-steps of effective data screening and abnormal data screening; issuing data acquisition commands for m times when data are acquired each time, and acquiring n groups of data successfully, then performing effective data screening and abnormal data screening on the n groups of data in sequence; the effective data screening is to primarily screen the n groups of data according to the range of the sensor, eliminate the ineffective data beyond the range of the sensor, and leave n2Group data; the abnormal data is screened for the remaining n according to the Grabbs test method2The data acquisition level was 5%, defining the threshold value Gp (n) for the Grabbs test2) And calculating the remainder n in turn2Mean of group data
Standard deviation of
And the Grabbs test statistic for each group number
Selecting the remaining n2Maximum value of the Grabbs test statistic G in group datak(Gk＝max(Gi) Is analyzed if G is presentk＞Gp(n2) The k data is an abnormal value, the k data needs to be removed, and the rest n2＝n21 group of data is subjected to the abnormal data screening process again until Gk＜Gp(n2) If the residual data are not abnormal values, the residual data are reserved, the average value of the residual data is taken as the monitoring data after the screening of the current measurement result value, and the data screening is ended;
the screened monitoring data enter a data analysis module to carry out pipeline displacement analysis and pipeline strain/stress analysis; the pipeline displacement is directly calculated by using monitoring data according to a wavelength and displacement calculation formula under the premise of considering the temperature wavelength; the pipeline strain value of any position of the monitoring section can be obtained by calculation after eliminating the influence of temperature according to 3 groups of strain data on the monitoring section at the same moment, and the specific calculation steps are as follows:
the pipeline strain consists of film strain, y-direction bending strain and z-direction bending strain; the strain of the film at the monitored section, the maximum y-direction bending strain and the maximum z-direction bending strain are respectively set asm、
According to the superposition principle, the strain at any point on the section of the pipeline is obtained as shown in formula 1:
the monitoring strain values of the top and the left and the right sides of the pipeline are respectively U (0, r)o)、
It andm、
the relationship of (a) to (b) is as follows:
equation 2:
equation 3:
equation 4:
the monitored cross-sectional film strain and the maximum y-direction and z-direction bending expressed by the monitored strain are obtained from equations 2-4, respectively:
equation 5:
equation 6:
equation 7:
the maximum bending strain of the cross section can be obtained by combining the bending strains in the y and z directions, and the formula 8:
the angle at which the maximum bending strain is, equation 9:
accordingly, monitoring the cross-sectional maximum and minimum axial strain, equation 10:
axial strain at any point of the pipe section represented by the monitored strain, equation 11:
also, from the above equation, the maximum axial strain at each angle of the monitored cross section can be obtained, equation 12:
monitoring the cross-sectional average axial strain, equation 13:
monitoring the cross-sectional bending strain, equation 14:
obtaining maximum axial stress, average axial stress and bending stress values of each angle of the monitored section according to a pipeline stress-strain relation curve by a formula 12-a formula 14;
a monitoring and early warning module in the monitoring and early warning subsystem integrates the macroscopic displacement deformation and the stress state of the pipeline and issues early warning information by taking the intrinsic safety monitoring and early warning of the pipeline as a core; when the axial additional tensile and compressive stress values of the pipeline reach or exceed 30% of the axial additional tensile and compressive stress allowable values, blue early warning information is issued; when the axial additional tensile and compressive stress values of the pipeline reach or exceed 60% of the axial additional tensile and compressive stress allowable values, yellow early warning information is issued; and when the axial additional tensile and compressive stress values of the pipeline reach or exceed 90% of the axial additional tensile and compressive stress allowable values, red early warning information is issued.
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| CN113376024A (en) * | 2021-06-07 | 2021-09-10 | 中国水利水电科学研究院 | PCCP pipe burst monitoring and early warning system and method |
| CN113378269A (en) * | 2021-06-08 | 2021-09-10 | 中交隧道工程局有限公司 | Tunnel settlement deformation prediction method |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113376024A (en) * | 2021-06-07 | 2021-09-10 | 中国水利水电科学研究院 | PCCP pipe burst monitoring and early warning system and method |
| CN113378269A (en) * | 2021-06-08 | 2021-09-10 | 中交隧道工程局有限公司 | Tunnel settlement deformation prediction method |
| CN113378269B (en) * | 2021-06-08 | 2024-03-19 | 中交隧道工程局有限公司 | Tunnel settlement deformation prediction method |
| CN114184137A (en) * | 2021-12-15 | 2022-03-15 | 四川农业大学 | Tunnel deformation monitoring system and method based on long-gauge-length optical fiber sensing technology |
| CN114184137B (en) * | 2021-12-15 | 2023-06-06 | 四川农业大学 | Tunnel deformation monitoring system and method based on long gauge length optical fiber sensing technology |
| CN115046663A (en) * | 2022-08-12 | 2022-09-13 | 煤炭科学技术研究院有限公司 | Anchor rod stress monitoring method and anchor rod stress data analysis method |
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