CN112557196A - Quality inspection method for underground directly-buried pipeline - Google Patents
Quality inspection method for underground directly-buried pipeline Download PDFInfo
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- CN112557196A CN112557196A CN202011491826.4A CN202011491826A CN112557196A CN 112557196 A CN112557196 A CN 112557196A CN 202011491826 A CN202011491826 A CN 202011491826A CN 112557196 A CN112557196 A CN 112557196A
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- 238000000034 method Methods 0.000 title claims abstract description 37
- 238000007689 inspection Methods 0.000 title claims abstract description 7
- 238000001514 detection method Methods 0.000 claims abstract description 79
- 230000000670 limiting effect Effects 0.000 claims abstract description 20
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 77
- 238000004088 simulation Methods 0.000 claims description 46
- 238000012360 testing method Methods 0.000 claims description 44
- 238000001816 cooling Methods 0.000 claims description 26
- 238000010438 heat treatment Methods 0.000 claims description 25
- 238000006073 displacement reaction Methods 0.000 claims description 13
- 239000004576 sand Substances 0.000 claims description 5
- 239000013013 elastic material Substances 0.000 claims description 3
- 238000007667 floating Methods 0.000 claims description 3
- 230000035882 stress Effects 0.000 description 10
- 210000001503 joint Anatomy 0.000 description 9
- 235000017166 Bambusa arundinacea Nutrition 0.000 description 6
- 235000017491 Bambusa tulda Nutrition 0.000 description 6
- 241001330002 Bambuseae Species 0.000 description 6
- 235000015334 Phyllostachys viridis Nutrition 0.000 description 6
- 239000011425 bamboo Substances 0.000 description 6
- 230000006835 compression Effects 0.000 description 6
- 238000007906 compression Methods 0.000 description 6
- 238000009661 fatigue test Methods 0.000 description 6
- 238000011160 research Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 238000012544 monitoring process Methods 0.000 description 4
- 238000004364 calculation method Methods 0.000 description 3
- 238000010276 construction Methods 0.000 description 3
- 239000000498 cooling water Substances 0.000 description 3
- 239000010410 layer Substances 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 230000008602 contraction Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 239000008236 heating water Substances 0.000 description 2
- 230000002441 reversible effect Effects 0.000 description 2
- 239000002689 soil Substances 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000005485 electric heating Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000036961 partial effect Effects 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- 238000011895 specific detection Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
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- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N25/00—Investigating or analyzing materials by the use of thermal means
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/32—Investigating strength properties of solid materials by application of mechanical stress by applying repeated or pulsating forces
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/60—Investigating resistance of materials, e.g. refractory materials, to rapid heat changes
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Abstract
The invention discloses a quality inspection method for an underground directly-buried pipeline, which is characterized by comprising the steps of firstly obtaining the magnitude of an axial force applied to the pipeline under the action of a limiting factor, repeatedly stretching and compressing the two ends of the pipeline by using the axial force during detection, recording the cycle times until the pipeline generates fatigue, comparing the cycle times with a preset threshold, judging that the pipeline is unqualified if the cycle times are lower than the preset threshold, and judging that the pipeline is qualified if the cycle times are higher than the preset threshold. The invention can better detect the performance of the directly buried pipeline in the working state; the service life condition of the pipeline under the working state can be more accurately reflected, and whether the performance quality of the pipeline is qualified or not can be more quickly and accurately detected.
Description
Technical Field
The invention relates to the field of directly buried pipelines, in particular to a quality inspection method of a directly buried pipeline.
Background
The heat supply direct buried pipeline is the most commonly adopted pipeline laying mode in the central heat supply project in China. The operation safety of the heat supply direct-buried pipeline is in the aspects of urban work, life and the like. The current research shows that the heat supply direct-buried pipeline bears the complex load effects of dead weight, fluid pressure in the pipeline, static pressure of surrounding soil outside the pipeline, soil moving pressure of a motor vehicle and the like when working, and the determination of the stress state of the heat supply direct-buried pipeline is very complex. Therefore, how to research and detect the mechanical property of the heat supply direct-buried pipeline under the complex load action condition is a precondition for ensuring the safe operation of the heat supply direct-buried pipeline, and is also an important basis for designing, managing and evaluating the service life of the pipeline.
CN201720070768.5 discloses a test device for measuring the tangential shear strength of a prefabricated direct-buried heat-insulating pipeline, which comprises an outer holding tile sleeved outside a sample pipeline, clamping devices and torsion devices, wherein the clamping devices and the torsion devices are respectively arranged at two ends of the outer holding tile; the clamping device comprises an inner holding tile clamped and fixed on the outer side of the sample pipeline heat-insulating layer and a first limiting rod arranged on the inner holding tile, one end of the first limiting rod is fixed on the outer side wall of the inner holding tile, and the other end of the first limiting rod is clamped and fixed in a corresponding first groove; the torsion device comprises a second limiting rod clamped in the second groove and a connecting piece arranged on the second limiting rod, the second limiting rod and the outer holding tile are axially and vertically arranged, and the other end of the connecting piece is connected with a torque wrench. The utility model discloses a simple structure, the simple operation, the detection cost is low, and the scene of being convenient for and laboratory use.
CN201920608601.9 still discloses a test device of prefabricated direct-burried insulating tube tangential shear strength of survey, including mounting panel, base and support curb plate, the mounting panel is installed through the bolt to base top one end, the support curb plate is installed through the fixed slot to the base top other end, support the curb plate top and install the casing through the screw, servo motor is installed through the mount pad to bottom one end in the casing, mounting panel top one end welding has the slide rail, the slide rail top is provided with the installing support, servo motor's output shaft runs through the casing bottom and is connected with the lead screw, the lead screw outside cover is equipped with the silk piece, silk piece one end is connected with the stationary blade. The utility model discloses a convenience carries out the centre gripping to the insulating tube, can conveniently detect the pulling force size, can also conveniently take notes experimental data, is fit for being extensively promoted and used.
However, the above existing heat supply direct-buried pipeline test technologies only stay in the state of directly detecting the shear strength of the polyurethane heat-insulating layer and the steel pipe protective layer shell when the pipeline is not in operation. The method only belongs to the detection of the structural strength of the insulating layer, and the overall mechanical properties of the heat supply direct-buried pipeline and the pipe fittings thereof under the working state are not tested, particularly the primary stress failure, the secondary stress failure and the fatigue failure of peak stress of the medium pipeline and the pipe fittings thereof under the action of the pressure and the thermal stress of fluid. The detection research method is original and direct, the performance requirement of the pipeline in the real working state cannot be obtained, the test device is relatively simple as a production quality detection means, and the quality requirement of the directly buried pipeline cannot be better ensured.
Therefore, how to set a technology capable of better detecting the performance of the buried pipeline in the working state becomes a problem to be considered and solved by those skilled in the art.
Disclosure of Invention
Aiming at the defects of the prior art, the technical problems to be solved by the invention are as follows: how to provide a method for inspecting the quality of a buried pipeline at the ground, which can better detect the performance of the buried pipeline in a working state; the service life condition of the pipeline under the working state can be more accurately reflected, and whether the performance quality of the pipeline is qualified or not can be rapidly detected.
In order to solve the technical problems, the invention adopts the following technical scheme:
a quality inspection method for a directly buried pipeline at the ground is characterized in that the magnitude of an axial force applied to the pipeline under the action of a limiting factor is obtained, the axial force is adopted to repeatedly stretch and compress the two ends of the pipeline during detection, the cycle number until the pipeline generates a fatigue phenomenon is recorded, the cycle number is compared with a preset threshold value, if the cycle number is lower than the preset threshold value, the pipeline is judged to be unqualified, and if the cycle number is higher than the preset threshold value, the pipeline is judged to be qualified.
Therefore, the method adopts a mode of directly applying axial force change to the pipeline to replace internal stress change generated by the circulation alternation of cold water and hot water when the pipeline works, so that the cycle times of pipeline damage can be conveniently obtained in a short test time, and whether the pipeline is qualified or not can be judged more quickly and reliably.
The axial force applied to the pipeline under the action of the limiting factors can be obtained through theoretical calculation or detected directly by adopting a test device.
Further, during detection, the working state of the pipeline is simulated firstly. Thus, the detection accuracy can be improved better.
Further, the limiting factors include limiting temperature difference change and limiting water pressure effect.
Therefore, the force generated by the pipeline expanding with heat and contracting with cold in the axial direction and the force generated by the pipeline axial under the action of water pressure due to the temperature difference change (mainly the change of the water temperature of circulating water) are comprehensively considered, and the detection result can be more accurate and reliable.
Wherein, the fatigue phenomenon can be deformation or water leakage generated on the outer surface of the pipeline. The service life of the pipeline can be detected and judged by taking the service life as an evaluation.
Further, during detection, force is applied in the vertical direction of the pipeline to simulate the load condition in the vertical direction of the pipeline. Therefore, the vertical direction stress condition of the pipeline in actual working can be further deeply simulated, and the accuracy, reliability and the like of the test result are improved.
Furthermore, the temperature, the displacement and the strain force of the surface of the pipeline are detected during the test, and the data change condition is collected and recorded.
Therefore, whether the pipeline generates the fatigue phenomenon can be better monitored, and parameter basis can be provided for further pipeline performance research.
Specifically, the method comprises the steps of simulating and burying a pipeline in a container for test according to construction requirements, connecting two ends of the pipeline into a circulating heating water pipe to simulate the working water supply condition, carrying out axial constraint monitoring on the two ends of the pipeline and simulating the axial stress condition of the pipeline, recording the cycle times of the pipeline until the pipeline generates fatigue under different parameter factors, and judging whether the pipeline is qualified.
The specific detection process is realized by adopting the following fatigue test device, the test device comprises a simulation pipe groove, two ends of the lower part of the simulation pipe groove along the length direction are respectively provided with a hole for the end part of the detection pipeline to penetrate out, the fatigue test device also comprises a water supply simulation system, the water supply simulation system comprises a circulating water pipe, a circulating pump and a temperature control device, the circulating pump and the temperature control device are connected to the circulating water pipe, and two ends of the circulating water pipe are pipeline connecting ends for being connected with the detection pipeline; the pipeline axial restraint loading device is arranged outside holes at two ends of the simulation pipe groove and can provide axial restraint loading for the pipeline.
Therefore, when the testing device is used, the detection pipeline can be installed on the lower portion of the simulation pipe groove, the two ends of the detection pipeline are exposed from the holes, then backfill sand is filled in the simulation pipe groove to bury the detection pipeline, the pipeline connecting end of the circulating water pipe is connected with the two ends of the detection pipeline, the pipeline axial constraint loading device is installed on the two ends of the pipeline to form axial constraint, the circulating pump is used for providing circulating water for the detection pipeline, the temperature control device is used for controlling water temperature, the circulating pump is used for controlling flow and water pressure, and the actual working condition of the pipeline is simulated. Therefore, the device can perform fatigue test detection under the condition of simulating the actual working condition of the pipeline, check and evaluate the real fatigue limit value and the service life of the pipeline, and judge whether the product is qualified.
Furthermore, the temperature control device comprises a heating pipeline and a cooling pipeline, the heating pipeline and the cooling pipeline are connected in parallel to the circulating water pipe, the heating pipeline is provided with a heating device and a valve for control, and the cooling pipeline is provided with a cooling device and a valve for control.
Therefore, during test or detection control, the heating pipeline can be firstly opened to start the heating device, hot water is provided for the detection pipeline, after one-time circulation or a plurality of times, the cooling pipeline is switched to provide cold water for the detection pipeline, and the one-time circulation of the simulation heating pipeline is finished. Therefore, cold water and hot water are supplied repeatedly and alternately, and the performance change of the pipeline in a cold and hot alternating circulation state can be detected better.
Furthermore, the water supply simulation system also comprises a simulation cooling device which is connected in series in the circulating water pipe.
Therefore, the simulation cooling device can simulate the user heating condition, the hot water of the primary heat supply circulation is cooled and then returns to the control end, and the cooling water supply is conveniently switched.
Furthermore, the pipeline connecting end of the circulating water pipe comprises a plug which is in a frustum shape made of elastic materials, the small diameter end of the plug is smaller than the inner diameter of the detection pipeline, the large diameter end of the plug is larger than the inner diameter of the pipeline, and the circulating water pipe penetrates out of the large diameter end of the plug to the small diameter end.
Like this, can convenient and fast ground realize circulating pipe and the connection that detects the pipeline, avoid leaking, and adopt the mode of shutoff to connect, can avoid better and produce the interference with pipeline axial restraint loading device.
Furthermore, the pipeline axial restraint loading device comprises a load loading device, the load loading device is provided with a telescopic shaft which is just opposite to the axis direction of the detection pipeline, the front end of the telescopic shaft is provided with a connector which is fixedly connected with the end part of the detection pipeline, a force measuring sensor capable of detecting the axial load is arranged in the connector, and the force measuring sensor is connected with the control center.
Therefore, the load loading device can not only provide axial restraint for the detection pipeline, but also simulate the condition of axial restraint when the pipeline is buried for use. Meanwhile, the axial load of the detection pipeline can be actively loaded, and the change condition of the axial load caused by expansion with heat and contraction with cold when the detection pipeline is subjected to cold and heat changes is directly simulated. In the method, based on the mode, forward and reverse repeated loading (namely repeated compression and stretching) can be actively carried out on the axial load of the pipeline in the test to simulate the condition of the cold and hot water exchange cycle of the pipeline. Therefore, the cold and hot water circulation is replaced by the axial tension and compression circulation which is directly applied to the pipeline, and the test time can be greatly shortened.
Further, the connector, including a ring flange that is located the front end and is used for and detect the pipeline butt joint, an butt joint section of thick bamboo of coaxial fixedly connected with on the ring flange rear end face, the circulating pipe groove of stepping down has been seted up on the butt joint section of thick bamboo, butt joint section of thick bamboo rear end is fixed with a mounting panel, be connected with a first connecting plate that is L shape backward on the mounting panel, form one between first connecting plate and the mounting panel and detect the chamber, the connector still includes a second connecting plate of fixing on the telescopic shaft, the second connecting plate front end is L shape and pegs graft into and detect the chamber, the second connecting plate is located and detects the front and back both sides of part in the chamber and respectively is provided with a force cell.
Therefore, the force measuring sensor on the front side of the second connecting plate can more accurately detect and monitor the pressure when the telescopic shaft stretches out to load the pressure, and the force measuring sensor on the rear side of the second connecting plate can more accurately detect and monitor the tension when the telescopic shaft retracts to apply the tension; therefore, the loading monitoring of the compression and the tension of the detection pipeline can be more accurate and reliable in the test or detection process. When the device is used, after the circulating water pipe is installed on a detection pipeline, the flange plate is butted with the flange plate at the end part of the detection pipeline (if the detection pipeline is a pipeline without the flange plate, the flange plate is welded at the end part of the pipeline firstly), and the circulating water pipe is led out from the circulating water pipe abdicating groove on the butting cylinder. Therefore, the connector structure has the advantages of simple structure, stable and reliable force transmission and no interference when being matched with a circulating water pipe.
The device further comprises a data acquisition system, wherein the data acquisition system comprises a plurality of groups of strain gauges, displacement sensors and temperature sensors which are arranged on the surface of the detection pipeline at intervals, and the strain gauges, the displacement sensors and the temperature sensors are connected with a control center.
Therefore, the strain, the displacement and the temperature of the detection pipeline in the test or detection process can be monitored and recorded in the test or detection process, and when the strain and the displacement reach preset threshold values, the fatigue phenomenon can be judged to be generated; or may be used to monitor strain and displacement to control them at a predetermined threshold for testing.
Further, still include vertical load analogue means, vertical load analogue means is including being located the apron of simulation tube seat upper end, and the lid is established on the backfill sand and keeps all around and is the state of floating with simulation tube seat lateral wall when the apron uses, is provided with portable dolly on the apron.
Therefore, the actual working condition of the pipeline arranged below the road can be directionally simulated, the weight and the moving speed of the movable trolley can be set according to the characteristics of the motor vehicles borne on the actual pipeline. The data obtained in this way can reflect the performance of the pipeline under the road more truly.
In conclusion, the invention can better detect the performance of the directly buried pipeline in the working state; the service life condition of the pipeline under the working state can be more accurately reflected, and whether the performance quality of the pipeline is qualified or not can be more quickly and accurately detected.
Drawings
FIG. 1 is a schematic view of a test apparatus used in the practice of the present invention.
Fig. 2 is a partial structural schematic view of the single connector in fig. 1.
FIG. 3 is a schematic illustration of an angled bend test in the practice of the present invention.
FIG. 4 is a schematic diagram of a pipeline test using a reducer pipe in the practice of the present invention.
FIG. 5 is a schematic diagram of a pipeline test using a pipe with a bevel angle in the practice of the present invention.
FIG. 6 is a schematic diagram of a pipeline test using a tee in the practice of the present invention.
FIG. 7 is a schematic diagram of another configuration of a water supply simulation system in accordance with the practice of the present invention. Detailed Description
The present invention will be described in further detail with reference to specific embodiments.
In the specific implementation: referring to figures 1-2 (in which the arrows indicate the direction of flow),
a method for testing the quality of underground pipeline includes such steps as obtaining the axial force of pipeline under the action of extreme factors, repeating the stretching and compressing cycles of pipeline to both ends, recording the number of cycles until the pipeline is fatigued, comparing the number of cycles with a predefined threshold, judging if the number of cycles is less than the predefined threshold, and if it is greater than the predefined threshold, judging if the number of cycles is not greater than the predefined threshold.
Therefore, the method adopts a mode of directly applying axial force change to the pipeline to replace internal stress change generated by the circulation alternation of cold water and hot water when the pipeline works, so that the cycle times of pipeline damage can be conveniently obtained in a short test time, and whether the pipeline is qualified or not can be judged more quickly and reliably. In implementation, the preset threshold value may be obtained by calculation or by a standard pipeline test.
The axial force applied to the pipeline under the action of the limiting factors can be obtained through theoretical calculation or detected directly by adopting a test device.
During detection, the working state of the pipeline is simulated firstly. Thus, the detection accuracy can be improved better.
Wherein the limiting factors comprise limiting temperature difference change and limiting water pressure action.
Therefore, the force generated by the pipeline expanding with heat and contracting with cold in the axial direction and the force generated by the pipeline axial under the action of water pressure due to the temperature difference change (mainly the change of the water temperature of circulating water) are comprehensively considered, and the detection result can be more accurate and reliable.
Wherein, the fatigue phenomenon can be deformation or water leakage generated on the outer surface of the pipeline. The service life of the pipeline can be judged by testing by taking the service life as an evaluation.
In the implementation process, force can be applied in the vertical direction of the pipeline to simulate the load condition in the vertical direction.
Therefore, the vertical direction stress condition of the pipeline in actual working can be further deeply simulated, and the accuracy, reliability and the like of the test result are improved.
During detection, the temperature, the displacement and the strain force of the surface of the pipeline can be detected, and the data change condition of the pipeline can be acquired and recorded.
Therefore, whether the pipeline generates the fatigue phenomenon can be better monitored, and parameter basis can be provided for further pipeline performance research.
Specifically, the method comprises the steps of simulating and burying a pipeline in a container for test according to construction requirements, connecting two ends of the pipeline into a circulating heating water pipe to simulate the working water supply condition, carrying out axial constraint monitoring on the two ends of the pipeline and simulating the axial stress condition of the pipeline, recording the cycle times of the pipeline until the pipeline generates fatigue under different parameter factors, and judging whether the pipeline is qualified.
The method is implemented by adopting the fatigue test device shown in the figure 1-2, the test device comprises a simulation pipe tank 1, two ends of the lower part of the simulation pipe tank 1 along the length direction are respectively provided with a hole 2 for the end part of a detection pipeline 4 to penetrate out, the fatigue test device also comprises a water supply simulation system, the water supply simulation system comprises a circulating water pipe 3, a circulating pump 5 and a temperature control device, the circulating pump 5 and the temperature control device are connected to the circulating water pipe, and two ends of the circulating water pipe 3 are pipeline connecting ends for connecting the detection pipeline 4; the pipeline axial restraint loading device is arranged outside holes at two ends of the simulation pipe groove and can provide axial restraint loading for the pipeline.
Therefore, when the testing device is used, the detection pipeline can be installed on the lower portion of the simulation pipe groove, the two ends of the detection pipeline are exposed from the holes, then backfill sand is filled in the simulation pipe groove to bury the detection pipeline, the pipeline connecting end of the circulating water pipe is connected with the two ends of the detection pipeline, the pipeline axial constraint loading device is installed on the two ends of the pipeline to form axial constraint, the circulating pump is used for providing circulating water for the detection pipeline, the temperature control device is used for controlling water temperature, the circulating pump is used for controlling flow and water pressure, and the actual working condition of the pipeline is simulated. Therefore, the device can perform fatigue test detection under the condition of simulating the actual working condition of the pipeline, check and evaluate the real fatigue limit value and the service life of the pipeline, and judge whether the product is qualified.
The temperature control device comprises a heating pipeline and a cooling pipeline, the heating pipeline and the cooling pipeline are connected in parallel to the circulating water pipe, a heating device 6 and a valve for control are arranged on the heating pipeline, and a cooling device 7 and a valve for control are arranged on the cooling pipeline.
Therefore, during test or detection control, the heating pipeline can be firstly opened to start the heating device, hot water is provided for the detection pipeline, after one-time circulation or a plurality of times, the cooling pipeline is switched to provide cold water for the detection pipeline, and the one-time circulation of the simulation heating pipeline is finished. Therefore, cold water and hot water are supplied repeatedly and alternately, and the performance change of the pipeline in a cold and hot alternating circulation state can be detected better. Wherein heating device can adopt electric heating module heating, convenient control. The cooling device may be cooled by heat exchange with a (flowing) cooling water reservoir. Each of which may be of conventional construction and will not be described in detail herein.
Wherein, the water supply simulation system also comprises a cooling device 8 for simulation, and the cooling device for simulation is connected in series in the circulating water pipe.
Therefore, the simulation cooling device can simulate the user heating condition, the hot water of the primary heat supply circulation is cooled and then returns to the control end, and the cooling water supply is conveniently switched.
In specific implementation, the water supply simulation system can also adopt the structural mode shown in fig. 7, that is, the heating pipeline, the cooling pipeline and the simulation cooling device are respectively connected in parallel with a valve and then connected in series with the heating pipeline. Therefore, the heating pipeline, the cooling pipeline and the cooling device for simulation can be conveniently switched and controlled to work according to needs.
Wherein, circulating pipe 3's pipe connection end includes a end cap 9, and the end cap is elastic material's frustum shape, and its minor diameter end is less than the detection pipeline internal diameter, and major diameter end is greater than the pipeline internal diameter, and circulating pipe wears out the minor diameter end from end cap major diameter end.
Like this, can convenient and fast ground realize circulating pipe and the connection that detects the pipeline, avoid leaking, and adopt the mode of shutoff to connect, can avoid better and produce the interference with pipeline axial restraint loading device.
The pipeline axial constraint loading device comprises a load loading device 10, wherein the load loading device 10 is provided with a telescopic shaft 11 which is just opposite to the axis direction of a detection pipeline, the front end of the telescopic shaft 11 is provided with a connector 12 which is fixedly connected with the end part of the detection pipeline, a force measuring sensor 13 capable of detecting the axial load is arranged in the connector 12, and the force measuring sensor 13 is connected with a control center 14.
Therefore, the load loading device can not only provide axial restraint for the detection pipeline, but also simulate the condition of axial restraint when the pipeline is buried for use. Meanwhile, the axial load of the detection pipeline can be actively loaded, and the change condition of the axial load caused by expansion with heat and contraction with cold when the detection pipeline is subjected to cold and heat changes is directly simulated. In the method, based on the mode, forward and reverse repeated loading (namely repeated compression and stretching) can be actively carried out on the axial load of the pipeline in the test to simulate the condition of the cold and hot water exchange cycle of the pipeline. Therefore, the cold and hot water circulation is replaced by the axial tension and compression circulation which is directly applied to the pipeline, and the test time can be greatly shortened.
The load loading device can be a power device such as an electric push rod, an electric cylinder, a hydraulic cylinder and the like, and the specific structure is not detailed here.
Wherein, the connector, including one be located the front end be used for with detect the ring flange 15 of pipeline butt joint, a butt joint section of thick bamboo 16 of coaxial fixedly connected with on the ring flange 15 rear end face, the last circulating pipe groove of stepping down of having seted up of butt joint section of thick bamboo 16, butt joint section of thick bamboo rear end is fixed with a mounting panel 17, be connected with a first connecting plate 18 that is L shape backward on the mounting panel 17, form a detection chamber between first connecting plate 18 and the mounting panel, the connector still includes a second connecting plate 19 of fixing on the telescopic shaft, 19 front ends of second connecting plate are L shape and peg graft into and detect the chamber, second connecting plate 19 is located the front and back both sides of detecting the intracavity part and respectively is provided with a dynamometry sensor 13.
Therefore, the force measuring sensor on the front side of the second connecting plate can more accurately detect and monitor the pressure when the telescopic shaft stretches out to load the pressure, and the force measuring sensor on the rear side of the second connecting plate can more accurately detect and monitor the tension when the telescopic shaft retracts to apply the tension; therefore, the loading monitoring of the compression and the tension of the detection pipeline can be more accurate and reliable in the test or detection process. When the device is used, after the circulating water pipe is installed on a detection pipeline, the flange plate is butted with the flange plate at the end part of the detection pipeline (if the detection pipeline is a pipeline without the flange plate, the flange plate is welded at the end part of the pipeline firstly), and the circulating water pipe is led out from the circulating water pipe abdicating groove on the butting cylinder. Therefore, the connector structure has the advantages of simple structure, stable and reliable force transmission and no interference when being matched with a circulating water pipe.
The system further comprises a data acquisition system, wherein the data acquisition system comprises a plurality of groups of strain gauges 20, displacement sensors 21 and temperature sensors 22 which are arranged on the surface of the detection pipeline at intervals, and the strain gauges, the displacement sensors and the temperature sensors are connected with the control center 14.
Therefore, the strain, the displacement and the temperature of the detection pipeline in the test or detection process can be monitored and recorded in the test or detection process, and when the strain and the displacement reach preset threshold values, the fatigue phenomenon can be judged to be generated.
The simulation device comprises a simulation pipe groove, a vertical load simulation device and a movable trolley 24, wherein the vertical load simulation device comprises a cover plate positioned at the upper end of the simulation pipe groove, the cover plate is covered on backfill sand when in use and keeps a floating state with the side wall of the simulation pipe groove at the periphery, and the movable trolley 24 is arranged on the cover plate.
Therefore, the actual working condition of the pipeline arranged below the road can be directionally simulated, the weight and the moving speed of the movable trolley can be set according to the characteristics of the motor vehicles borne on the actual pipeline. The data obtained in this way can reflect the performance of the pipeline under the road more truly.
In addition, referring to fig. 3 to 6, the present invention can also be used for testing and detecting pipe fittings or pipelines such as bent pipes with angles, pipe fittings with reducing diameters, pipe fittings with bevel angles, pipe fittings with tee joints, etc. when the present invention is implemented, the specific process is consistent with the above, only the device part needs to be slightly adjusted according to the needs, and the detailed process is not described herein.
Claims (10)
1. A quality inspection method for a directly buried pipeline at the ground is characterized in that the magnitude of an axial force applied to the pipeline under the action of a limiting factor is obtained, the axial force is adopted to repeatedly stretch and compress the two ends of the pipeline during detection, the cycle number until the pipeline generates a fatigue phenomenon is recorded, the cycle number is compared with a preset threshold value, if the cycle number is lower than the preset threshold value, the pipeline is judged to be unqualified, and if the cycle number is higher than the preset threshold value, the pipeline is judged to be qualified.
2. The method for inspecting the quality of the underground pipeline as claimed in claim 1, wherein during the inspection, the simulation of the working state of the pipeline is performed.
3. The method for inspecting the quality of the underground pipeline according to claim 1, wherein the limiting factors comprise a limiting temperature difference change and a limiting hydraulic pressure action;
and during detection, force is applied in the vertical direction of the pipeline to simulate the load condition borne by the pipeline in the vertical direction.
4. The method for inspecting the quality of the underground buried pipeline according to claim 1, wherein the method is implemented by using a testing device, the testing device comprises a simulation pipe groove, two ends of the lower part of the simulation pipe groove along the length direction are respectively provided with a hole for the end part of the detection pipeline to penetrate out, the testing device further comprises a water supply simulation system, the water supply simulation system comprises a circulating water pipe, a circulating pump and a temperature control device, the circulating pump and the temperature control device are connected to the circulating water pipe, and the two ends of the circulating water pipe are pipeline connecting ends for being connected with the detection pipeline; the pipeline axial restraint loading device is arranged outside holes at two ends of the simulation pipe groove and can provide axial restraint loading for the pipeline.
5. The method for inspecting the quality of the underground pipeline according to claim 4, wherein the temperature control device comprises a heating pipeline and a cooling pipeline, the heating pipeline and the cooling pipeline are connected in parallel to the circulating water pipe, the heating pipeline is provided with a heating device and a valve for control, and the cooling pipeline is provided with a cooling device and a valve for control.
6. The method for inspecting the quality of the underground pipeline according to claim 5, wherein the water supply simulation system further comprises a cooling device for simulation, and the cooling device for simulation is connected in series to the circulating water pipe.
7. The method for testing the quality of the underground buried pipeline according to claim 4, wherein the pipeline connecting end of the circulating water pipe comprises a plug, the plug is in the shape of a frustum of an elastic material, the small diameter end of the plug is smaller than the inner diameter of the detection pipeline, the large diameter end of the plug is larger than the inner diameter of the pipeline, and the circulating water pipe penetrates out of the large diameter end of the plug to the small diameter end.
8. The method for testing the quality of the underground pipeline as claimed in claim 4, wherein the axial constraint loading device for the pipeline comprises a load loading device, the load loading device is provided with a telescopic shaft which is opposite to the axial direction of the detection pipeline, the front end of the telescopic shaft is provided with a connector which is fixedly connected with the end part of the detection pipeline, a force sensor which can detect the magnitude of the axial load is arranged in the connector, and the force sensor is connected with the control center.
9. The method for inspecting the quality of the underground pipeline as claimed in claim 8, wherein the connector comprises a flange plate at the front end for butting against the detection pipeline, a butting cylinder is coaxially and fixedly connected to the rear end face of the flange plate, a circulating water pipe receding groove is formed in the butting cylinder, a mounting plate is fixed to the rear end of the butting cylinder, an L-shaped first connecting plate is connected to the mounting plate in the backward direction, a detection cavity is formed between the first connecting plate and the mounting plate, the connector further comprises a second connecting plate fixed to the telescopic shaft, the front end of the second connecting plate is L-shaped and inserted into the detection cavity, and force sensors are respectively arranged at the front side and the rear side of the part of the second connecting plate located in the detection cavity.
10. The method for inspecting the quality of the underground buried pipeline according to claim 4, further comprising a data acquisition system, wherein the data acquisition system comprises a plurality of groups of strain gauges, displacement sensors and temperature sensors which are arranged on the surface of the detection pipeline at intervals, and the strain gauges, the displacement sensors and the temperature sensors are connected with a control center;
the vertical load simulator comprises a cover plate positioned at the upper end of the simulation pipe groove, the cover plate is arranged on backfill sand in a covering mode when in use, the periphery of the cover plate is kept to be in a floating state with the side wall of the simulation pipe groove, and a movable trolley is arranged on the cover plate.
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| CN202011491826.4A CN112557196B (en) | 2020-12-17 | Quality inspection method for underground direct-buried pipeline |
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| CN114777634A (en) * | 2022-04-06 | 2022-07-22 | 中国石油化工股份有限公司 | System and method for testing stress of buried pipeline under vehicle load |
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