Experimental device for measuring interaction between frozen soil and buried pipeline and preparation method
阅读说明：本技术 测量冻土与埋地管道相互作用的实验装置及制备方法 (Experimental device for measuring interaction between frozen soil and buried pipeline and preparation method ) 是由 滕振超 刘宇 赵誉翔 张云峰 李文 詹界东 于 2019-12-24 设计创作，主要内容包括：一种测量冻土与埋地管道相互作用的实验装置及制备方法,涉及实验模型技术领域,它包括车型箱体,车型箱体由两块横向钢板、两块侧向钢板和一块底面钢板所围成的开口箱体结构,车型箱体一侧壁穿有前端部管道,前端部管道伸入车型箱体内的一端与中间管道一端通过法兰盘焊接,中间管道另一端通过法兰盘与后端部管道一端焊接,前端部管道、中间管道和后端部管道上贴有应变片,应变片通过导线与静态电阻应变仪连接；车型箱体内铺设土层,土层内安装温度探针,温度探针通过导线与静态电阻应变仪连接。本测量冻土与埋地管道相互作用的实验装置及制备方法通过实验土温度的变化和管道的应变情况,准确的测量出冻土与埋地管道相互作用的关系。(An experimental device for measuring interaction between frozen soil and a buried pipeline and a preparation method thereof relate to the technical field of experimental models and comprise a vehicle-shaped box body, wherein the vehicle-shaped box body is of an open box body structure surrounded by two transverse steel plates, two lateral steel plates and a bottom steel plate, a front end part pipeline penetrates through one side wall of the vehicle-shaped box body, one end of the front end part pipeline, which extends into the vehicle-shaped box body, is welded with one end of a middle pipeline through a flange plate, the other end of the middle pipeline is welded with one end of a rear end part pipeline through a flange plate, strain gauges are adhered to the front end part pipeline, the middle pipeline and the rear end part pipeline, and the strain gauges are connected with a; lay the soil layer in the motorcycle type box, install temperature probe in the soil layer, temperature probe passes through the wire and is connected with static resistance strain gauge. The experimental device and the preparation method for measuring the interaction between the frozen soil and the buried pipeline accurately measure the interaction relationship between the frozen soil and the buried pipeline through the change of the experimental soil temperature and the strain condition of the pipeline.)
1. The utility model provides a measure frozen soil and buried pipeline interact's experimental apparatus which characterized in that: the device comprises a vehicle-type box body (1), wherein the vehicle-type box body (1) is of an open box body structure surrounded by two transverse steel plates (5), two lateral steel plates (6) and a bottom steel plate (7), a front end pipeline (2) penetrates through one side wall of the vehicle-type box body (1), one end, extending into the vehicle-type box body (1), of the front end pipeline (2) is welded with one end of a middle pipeline through a flange plate (4), the other end of the middle pipeline is welded with one end of a rear end pipeline (3) through the flange plate (4), the other end of the rear end pipeline (3) penetrates out of the vehicle-type box body (1), strain gauges are attached to the front end pipeline (2), the middle pipeline and the rear end pipeline (3), and the strain gauges are connected with a static resistance strain gauge through a; a soil layer is laid in the vehicle-shaped box body (1), a temperature probe is installed in the soil layer, and the temperature probe is connected with the static resistance strain gauge through a wire.
2. The experimental facility for measuring frozen soil interaction with buried pipelines according to claim 1, wherein: handrails (8) are welded on the side walls of lateral steel plates (6) of the vehicle-shaped box body (1), and rolling wheels are installed at the bottom of the vehicle-shaped box body (1).
3. The experimental facility for measuring frozen soil interaction with buried pipelines according to claim 1, wherein: the outer portions of the two transverse steel plates (5) and the two lateral steel plates (6) are respectively adhered with a benzene plate (10), the thickness of the benzene plate is 40-60 mm, an iron sheet protective layer (11) is arranged on the periphery of the benzene plate (10), and the thickness of the iron sheet protective layer (11) is 0.5-1.5 mm.
4. The experimental facility for measuring frozen soil interaction with buried pipelines according to claim 1, wherein: aiming rods (12) are welded on two side walls of the vehicle-shaped box body (1); preceding tip pipeline (2), middle pipeline and back tip pipeline (3) top all weld and have sign pole (14), sign pole (14) overcoat has plastic sleeve (15), plastic sleeve (15) diameter is 13 ~ 15mm, sign pole (14) and aim at pole (13) and be the steel bar column, the diameter of steel bar column is 9 ~ 11 mm.
5. The experimental facility for measuring frozen soil interaction with buried pipelines according to claim 1, wherein: one end of the front end pipeline (2) extends out of the vehicle-shaped box body (1) by 9-11 cm and is welded with an outer channel; one end of the rear end pipeline (3) extends out of the vehicle-shaped box body (1) by 9-11 cm, and a water storage release valve (9) is arranged on the pipeline; the automobile type box body (1) is characterized in that two drainage sieve holes (12) are formed in a bottom steel plate (7), the two drainage sieve holes (12) are located on the diagonal line, and the diameters of the drainage sieve holes (12) are 90-110 mm.
6. The experimental facility for measuring frozen soil interaction with buried pipelines according to claim 1, wherein: the thicknesses of the transverse steel plate (5), the lateral steel plate (6) and the bottom steel plate (7) are 3-5 mm; the thickness of the front end pipeline (2), the middle pipeline and the rear end pipeline (3) is 1.0-2.0 mm.
7. The experimental facility for measuring frozen soil interaction with buried pipelines according to claim 1, wherein: the pipeline walls of the front end pipeline (2), the middle pipeline and the rear end pipeline (3) are all adhered with four strain gauges which are evenly distributed on the circumferential surface of the pipeline.
8. The experimental facility for measuring frozen soil interaction with buried pipelines according to claim 1, wherein: the temperature probe number be a plurality of, from top to bottom, from left to right and right front to back all have to arrange, interval between temperature probe and the temperature probe increases step by step when arranging from top to bottom.
9. The experimental facility for measuring frozen soil interaction with buried pipelines according to claim 1, wherein: and a temperature controller is arranged in the middle pipeline.
10. A method for preparing the experimental device for measuring the interaction of the frozen soil and the buried pipeline according to claim 1, which is characterized in that: the manufacturing method comprises the following steps:
1) assembling soil samples, namely screening the experimental soil samples before experiments, selecting the experimental soil with proper water content and the like, dividing the experimental soil into five layers, filling the five layers of experimental soil into an experimental vehicle-shaped box body (1), controlling the thickness of each layer to be 20cm, compacting the layers layer by layer, compacting each layer of soil sample by using a wooden hammer to enable the soil sample to reach natural soil density until the three layers of soil samples are filled completely, and enabling the height of the soil sample to reach the lower edge of a two-thirds pipeline at the height of the vehicle-shaped box body (1);
2) marking measuring points on a pipeline, sticking strain gauges at the measuring points, sticking the strain gauges to the pipeline in a vehicle-type box body (1), in order to determine the main stress direction of the pipeline, adopting a triaxial strain pattern form, totally dividing into five groups, measuring the axial circumferential strain of the pipeline by using a group of four measuring points, further calculating the main stress magnitude and direction of the pipeline, connecting a lead, putting a temperature controller in the middle pipeline in advance, connecting the middle pipeline with a front-end pipeline (2) and a rear-end pipeline (3) welded on the box body through a flange (4), and checking the compactness of the connected pipelines;
3) manufacturing a temperature probe, drilling 3-6 small holes with the diameter of 0.5mm on a plastic pipe at regular intervals, gradually increasing the distance of the small holes from top to bottom according to the distribution rule of a temperature field, penetrating a thermocouple through the plastic pipe and out of the small holes, and slightly exposing the head of the thermocouple to form the small holes, wherein in order to ensure that the thermocouple is well contacted with a soil body, a resin adhesive is used for coating the head of the thermocouple to achieve the effects of insulation and sealing, a thermocouple lead is led out from the other side of the plastic pipe and is fixed in a junction box, and the other end of the plastic pipe is sealed by a plug, so that the temperature probe is;
4) a temperature probe is placed in a soil body, an insertion pipe is adopted to arrange the temperature probe (thermocouple), a reserved lead and a temperature probe test wire which are connected with a strain gauge are connected with a static resistance strain gauge through leads, and the temperature probe is utilized to measure the temperature change of each position of the soil body;
5) after the temperature probes are embedded, soil samples are continuously assembled, the thickness of each layer is 20cm, two layers are assembled until the vehicle-shaped box body (1) is filled, and the soil samples are compacted layer by layer to reach the natural soil density;
6) and (3) testing the connected experimental device, performing a freeze-thaw cycle experiment according to different requirements of the experiment, determining the specific cycle time of the freeze-thaw cycle, setting the cycle conditions according to the cycle, namely, after the device is placed in an indoor environment with the temperature of 15-20 ℃ for 48 hours, placing the device in an outdoor environment with the temperature of-15 to-20 ℃ for 48 hours, performing the freeze-thaw cycle once every 96 hours, and measuring the strain change inside and outside the pipeline in real time through a static resistance strain gauge.
The technical field is as follows:
the invention relates to the technical field of experimental models, in particular to an experimental device for measuring interaction between frozen soil and a buried pipeline and a preparation method thereof.
Background art:
the transportation of petroleum and natural gas is closely related to national economy and people's life, the pipeline transportation has the characteristics of safety, convenience and economy, the buried pipeline is widely applied in the petroleum transportation, but the pipeline is easy to generate the adverse phenomena of frost heaving, thaw collapse and the like in a frozen soil area due to the influence of factors such as a soil body temperature field, the thickness of a frozen soil layer and the like, particularly the freeze-thaw cycle phenomenon in alternate seasons. At present, the research on the buried oil pipeline is also established in the field experiment and finite element simulation research stage, the damage of the soil body freeze-thaw cycle to the buried oil pipeline is difficult to observe through a large-scale experiment simulation device in a laboratory environment, and a large-scale experiment under different meteorological conditions cannot be simulated.
The invention content is as follows:
the invention aims to overcome the defects of the prior art and provides an experimental device for measuring the interaction between frozen soil and a buried pipeline and a preparation method thereof.
The technical scheme adopted by the invention is as follows: the experimental device comprises a vehicle-shaped box body, wherein the vehicle-shaped box body is of an open box body structure which is surrounded by two transverse steel plates, two lateral steel plates and a bottom steel plate, a front end pipeline penetrates through one side wall of the vehicle-shaped box body, one end of the front end pipeline, which extends into the vehicle-shaped box body, is welded with one end of an intermediate pipeline through a flange plate, the other end of the intermediate pipeline is welded with one end of a rear end pipeline through a flange plate, the other end of the rear end pipeline penetrates out of the vehicle-shaped box body, strain gauges are attached to the front end pipeline, the intermediate pipeline and the rear end pipeline, and the strain gauges are connected with a static resistance strain gauge through a lead; lay the soil layer in the motorcycle type box, install temperature probe in the soil layer, temperature probe passes through the wire and is connected with static resistance strain gauge.
Handrails are welded on the lateral steel plate side walls of the vehicle-shaped box body, and rolling wheels are installed at the bottom of the vehicle-shaped box body.
The outer portions of the two transverse steel plates and the two lateral steel plates are respectively adhered with a benzene plate, the thickness of the benzene plate is 40-60 mm, an iron sheet protective layer is arranged on the periphery of the benzene plate, and the thickness of the iron sheet protective layer is 0.5-1.5 mm.
Aiming rods are welded on two side walls of the vehicle-shaped box body; preceding tip pipeline, middle pipeline and back tip pipeline top all weld and have the marker post, the marker post overcoat has the plastics sleeve, the plastics sleeve diameter is 13 ~ 15mm, marker post and sighting rod are the steel bar column, the diameter of steel bar column is 9 ~ 11 mm.
One end of the front end pipeline extends out of the vehicle-shaped box body by 9-11 cm and is welded with an outer pipeline; one end of the rear end pipeline extends out of the vehicle-shaped box body by 9-11 cm, and a water storage release valve is arranged on the pipeline; the bottom surface steel plate of motorcycle type box on be equipped with two sluicing sieve meshes, two sluicing sieve meshes are located the diagonal, sluicing sieve mesh diameter is 90 ~ 110 mm.
The thickness of the transverse steel plate, the lateral steel plate and the bottom steel plate is 3-5 mm; the thickness of the front end pipeline, the middle pipeline and the rear end pipeline is 1.0-2.0 mm.
The pipeline walls of the front end pipeline, the middle pipeline and the rear end pipeline are all attached with four strain gauges which are evenly distributed on the circumferential surface of the pipeline.
The temperature probe number be a plurality of, from top to bottom, from left to right and right front to back all have to arrange, interval between temperature probe and the temperature probe increases step by step when arranging from top to bottom.
And a temperature controller is arranged in the middle pipeline.
The manufacturing method comprises the following steps:
1) assembling soil samples, namely screening the experimental soil samples before experiments, selecting the experimental soil with proper water content and the like, dividing the experimental soil into five layers, filling the five layers of experimental soil into an experimental vehicle-shaped box body (1), controlling the thickness of each layer to be 20cm, compacting the layers layer by layer, compacting each layer of soil sample by using a wooden hammer to enable the soil sample to reach natural soil density until the three layers of soil samples are filled completely, and enabling the height of the soil sample to reach the lower edge of a two-thirds pipeline at the height of the vehicle-shaped box body (1);
2) marking measuring points on a pipeline, sticking strain gauges at the measuring points, sticking the strain gauges to the pipeline in a vehicle-type box body (1), in order to determine the main stress direction of the pipeline, adopting a triaxial strain pattern form, totally dividing into five groups, measuring the axial circumferential strain of the pipeline by using a group of four measuring points, further calculating the main stress magnitude and direction of the pipeline, connecting a lead and placing the lead into an intermediate pipeline, placing a temperature controller in advance, connecting the intermediate pipeline with a front end pipeline (2) and a rear end pipeline (3) welded on the box body through flanges (4), and checking the compactness of the connected pipelines;
3) manufacturing a temperature probe, drilling 3-6 small holes with the diameter of 0.5mm on a plastic pipe at regular intervals, gradually increasing the distance of the small holes from top to bottom according to the distribution rule of a temperature field, penetrating a thermocouple through the plastic pipe and out of the small holes, and slightly exposing the head of the thermocouple to form the small holes, wherein in order to ensure that the thermocouple is well contacted with a soil body, a resin adhesive is used for coating the head of the thermocouple to achieve the effects of insulation and sealing, a thermocouple lead is led out from the other side of the plastic pipe and is fixed in a junction box, and the other end of the plastic pipe is sealed by a plug, so that the temperature probe is;
4) a temperature probe is placed in a soil body, an insertion pipe is adopted to arrange the temperature probe (thermocouple), a reserved lead and a temperature probe test wire which are connected with a strain gauge are connected with a static resistance strain gauge through leads, and the temperature probe is utilized to measure the temperature change of each position of the soil body;
5) after the temperature probes are embedded, soil samples are continuously assembled, the thickness of each layer is 20cm, two layers are assembled until the vehicle-shaped box body (1) is filled, and the soil samples are compacted layer by layer to reach the natural soil density;
6) and (3) testing the connected experimental device, performing a freeze-thaw cycle experiment according to different requirements of the experiment, determining the specific cycle time of the freeze-thaw cycle, setting the cycle conditions according to the cycle, namely, after the device is placed in an indoor environment with the temperature of 15-20 ℃ for 48 hours, placing the device in an outdoor environment with the temperature of-15 to-20 ℃ for 48 hours, performing the freeze-thaw cycle once every 96 hours, and measuring the strain change inside and outside the pipeline in real time through a static resistance strain gauge.
The invention has the following beneficial effects:
1) the device can be used for stress analysis of various buried pipelines under the action of freeze-thaw cycle, and can directly measure the stress state of the pipelines;
2) different temperatures of liquid in the pipeline can be simulated by arranging the temperature controller in the pipeline;
3) different soils are filled into the vehicle-shaped box body, so that the effect of various soils on the pipeline can be simulated;
4) the rolling wheels are arranged at the lower part of the device, so that the external environment of the experimental box body is easy to change, and the whole freezing-thawing cycle period environment can be simulated;
5) the change of the ambient temperature of the pipeline can be monitored in real time, the distribution and the change of the ambient temperature field of the pipeline in the whole freeze-thaw cycle period are described through information processing of a static resistance strain gauge and the like, and the change rule of the freeze-thaw cycle of the ambient freeze-thaw ring of the pipeline along with the freeze-thaw cycle is further analyzed;
6) the displacement settlement amount and the pipeline strain value of each part of the pipeline under the action of freeze-thaw cycle can be monitored in real time;
7) through information processing such as a static resistance strain gauge, the change rule of stress strain of the pipeline under the action of the whole freeze-thaw cycle can be detected.
Description of the drawings:
FIG. 1 is a front view of the present invention;
FIG. 2 is an exploded view of the present invention;
FIG. 3 is a top view of the present invention;
FIG. 4 is a cross-sectional view of the present invention;
FIG. 5 is a temperature probe layout of the present invention;
FIG. 6 is a top view of a strain gage distribution of the present invention;
FIG. 7 is a perspective view of a tube strain gage arrangement according to the present invention;
FIG. 8 is a cross-sectional view of a pipe strain gage arrangement according to the present invention.
The specific implementation mode is as follows:
referring to the figures, the experimental device for measuring the interaction between frozen soil and a buried pipeline and the preparation method thereof comprise a vehicle-
The manufacturing method comprises the following steps:
1) assembling soil samples, namely screening the experimental soil samples before experiments, selecting the experimental soil with proper water content and the like, dividing the experimental soil into five layers, filling the five layers of experimental soil into an experimental vehicle-shaped box body (1), controlling the thickness of each layer to be 20cm, compacting the layers layer by layer, compacting each layer of soil sample by using a wooden hammer to enable the soil sample to reach natural soil density until the three layers of soil samples are filled completely, and enabling the height of the soil sample to reach the lower edge of a two-thirds pipeline at the height of the vehicle-shaped box body (1);
2) marking measuring points on a pipeline, sticking strain gauges at the measuring points, sticking the strain gauges to the pipeline in a vehicle-type box body (1), in order to determine the main stress direction of the pipeline, adopting a triaxial strain pattern form, totally dividing into five groups, measuring the axial circumferential strain of the pipeline by using a group of four measuring points, further calculating the main stress magnitude and direction of the pipeline, connecting a lead, putting a temperature controller in the middle pipeline in advance, connecting the middle pipeline with a front-end pipeline (2) and a rear-end pipeline (3) welded on the box body through a flange (4), and checking the compactness of the connected pipelines;
3) manufacturing a temperature probe, drilling 3-6 small holes with the diameter of 0.5mm on a plastic pipe at regular intervals, gradually increasing the distance of the small holes from top to bottom according to the distribution rule of a temperature field, penetrating a thermocouple through the plastic pipe and out of the small holes, and slightly exposing the head of the thermocouple to form the small holes, wherein in order to ensure that the thermocouple is well contacted with a soil body, a resin adhesive is used for coating the head of the thermocouple to achieve the effects of insulation and sealing, a thermocouple lead is led out from the other side of the plastic pipe and is fixed in a junction box, and the other end of the plastic pipe is sealed by a plug, so that the temperature probe is;
4) a temperature probe is placed in a soil body, an insertion pipe is adopted to arrange the temperature probe (thermocouple), a reserved lead and a temperature probe test wire which are connected with a strain gauge are connected with a static resistance strain gauge through leads, and the temperature probe is utilized to measure the temperature change of each position of the soil body;
5) after the temperature probes are embedded, soil samples are continuously assembled, the thickness of each layer is 20cm, two layers are assembled until the vehicle-shaped box body (1) is filled, and the soil samples are compacted layer by layer to reach the natural soil density;
6) and (3) testing the connected experimental device, performing a freeze-thaw cycle experiment according to different requirements of the experiment, determining the specific cycle time of the freeze-thaw cycle, setting the cycle conditions according to the cycle, namely, after the device is placed in an indoor environment with the temperature of 15-20 ℃ for 48 hours, placing the device in an outdoor environment with the temperature of-15 to-20 ℃ for 48 hours, performing the freeze-thaw cycle once every 96 hours, and measuring the strain change inside and outside the pipeline in real time through a static resistance strain gauge.
The experimental environment is in a northeast cold area, the freezing and thawing temperature in the step 6) is only a reference value, the upper and lower freezing and thawing limits can be selected according to specific environments, when the lower temperature limit is lower than-20 ℃, the freezing and thawing circulation action can be correspondingly reduced, and other measures can be taken to realize a low-temperature environment, such as a freezing chamber and the like.
Because the time scale and the space scale involved in the pipeline heat transfer problem in the actual engineering are large, a reduced similarity model must be used for experiments, and according to a similar theoretical criterion,wherein, L is the characteristic length, m; gamma is the surface temperature variation period, s; f for ensuring experimental system and practical system0Without change, both have similar physical properties.
From similarity criterion number F0The form of (A) can be seen: in the reduced similarity model experiment, when the geometric scale is reduced by 10 times than the actual geometric scale, the time scale Γ is reduced by 100 times. According to 365 days per year, 365 multiplied by 24 is 8760 hours per year in practice, and the period of one year in the model experiment is 87.6 hours; 4d are continued and the course of the change in 1a in the actual system can be simulated.
The geometric length similarity ratio of the experimental device is approximately 10: 1, each freeze-thaw cycle period in the experiment is approximately controlled to be 98h, and other freeze-thaw cycles can be calculated according to similar theoretical criteria.
When the temperature probe is manufactured, the distance between the small holes is gradually increased from top to bottom according to the distribution rule of the temperature field, and the distance is selected according to a formula delta h which is 25n +100 (mm).
The device can monitor the ambient temperature change of the pipeline in real time, and can trace the distribution and the change of the ambient temperature field of the pipeline in the whole freeze-thaw cycle period through information processing, and further analyze the change rule of the freeze-thaw ring around the pipeline along with the freeze-thaw cycle. Experimental data show that 1) the change rule of the temperature of the soil around the pipeline along the depth direction along with time is similar to the change rule of the atmospheric temperature and basically conforms to the sine periodic change; 2) the amplitude of the temperature change curve is obviously attenuated along with the increase of the depth, and the temperature change curve conforms to the temperature change rule of the frozen soil area; 3) with the increase of the number of times of freeze-thaw cycles, the change rule of the area range of the freeze-thaw ring around the pipeline tends to be constant after increasing, and the specific parameters are related to the environment.
The device can monitor the displacement settlement amount and the strain value of the pipeline of each part of the pipeline under the action of freeze-thaw cycle in real time. Through information processing, the change rule of the stress strain of the pipeline under the action of the whole freeze-thaw cycle can be detected. Experimental data show that the integral strain of the pipeline continuously increases along with the increase of the number of freeze-thaw cycles, but the increment is gradually reduced, and the pipeline tends to be stable when the number of cycles is sufficient, and the upper limit of the specific number of cycles is influenced by factors such as the freeze-thaw temperature, the soil property and the like.
In order to reduce the friction between the steel bar column and the soil body, the plastic sleeve is sleeved outside the steel bar column.
The strain gauge used in the mutexperiment is a static resistance strain gauge DH3818Y produced by Jiangsu Donghua test, and the temperature probe (temperature sensor) is a temperature sensor JTNT-A produced by the technology of Jiantong in Beijing century, and can measure temperature and heat flow.
In conclusion, the experimental device for measuring the interaction between the frozen soil and the buried pipeline and the preparation method thereof can be used for stress analysis of various buried pipelines under the action of freeze-thaw cycles, and can directly measure the stress state of the pipelines; different temperatures of liquid in the pipeline can be simulated by arranging the temperature controller in the pipeline; different soils are filled into the vehicle-shaped box body, so that the effect of various soils on the pipeline can be simulated; the rolling wheels are arranged at the lower part of the device, so that the external environment of the experimental box body is easy to change, and the whole freezing-thawing cycle period environment can be simulated; the change of the ambient temperature of the pipeline can be monitored in real time, the distribution and the change of the ambient temperature field of the pipeline in the whole freeze-thaw cycle period are described through information processing of a static resistance strain gauge and the like, and the change rule of the freeze-thaw cycle of the ambient freeze-thaw ring of the pipeline along with the freeze-thaw cycle is further analyzed; the displacement settlement amount and the pipeline strain value of each part of the pipeline under the action of freeze-thaw cycle can be monitored in real time; through information processing such as a static resistance strain gauge, the change rule of stress strain of the pipeline under the action of the whole freeze-thaw cycle can be detected.
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