阅读说明：本技术 管道安全状态评估方法与阶梯式升压管道安全复产方法 (Pipeline safety state evaluation method and stepped boosting pipeline safety re-production method ) 是由 廖柯熹 朱洪东 何腾蛟 何国玺 李博阳 于 2019-11-08 设计创作，主要内容包括：本发明公开了一种管道安全状态评估方法与阶梯式升压管道安全复产方法,所述管道安全状态评估方法包括以下步骤：停输管道,踏勘,对滑坡管道进行定位；通过非接触式磁力计对滑坡管道进行磁检测,并利用所述非接触式磁力计配套软件观测记录所述滑坡管道沿线的磁信号数据；计算滑坡管道沿线力-磁关系综合指数M分布；评估滑坡管道的安全状态；所述阶梯式升压管道安全复产方法包括：根据上述方法评估管道安全状态,根据所述管道安全状态计算管道复产压力,根据所述管道复产压力实现管道安全复产。本发明能够准确检测应力集中位置,准确评估管道安全状态,实现管道安全复产。(The invention discloses a pipeline safety state evaluation method and a stepped boosting pipeline safety reproduction method, wherein the pipeline safety state evaluation method comprises the following steps of: stopping conveying the pipeline, performing reconnaissance, and positioning the landslide pipeline; performing magnetic detection on a landslide pipeline through a non-contact magnetometer, and observing and recording magnetic signal data along the landslide pipeline by utilizing software matched with the non-contact magnetometer; calculating the comprehensive index M distribution of the landslide pipeline along the linear force-magnetic relation; evaluating the safety state of the landslide pipeline; the safe production recovery method of the stepped booster pipeline comprises the following steps: and evaluating the safety state of the pipeline according to the method, calculating the pipeline reproduction pressure according to the safety state of the pipeline, and realizing the pipeline safety reproduction according to the pipeline reproduction pressure. The invention can accurately detect the stress concentration position, accurately evaluate the safety state of the pipeline and realize the safe production of the pipeline.)

1. A method for evaluating the safety state of a pipeline is characterized by comprising the following steps:

s1: stopping conveying the pipeline, performing reconnaissance, and positioning the landslide pipeline;

s2: performing magnetic detection on the landslide pipeline through a non-contact magnetometer, and observing and recording magnetic signal data along the landslide pipeline by using software matched with the non-contact magnetometer;

s3: calculating the comprehensive index M distribution of the landslide pipeline along the linear force-magnetic relation according to the magnetic signal data;

s4: according to the calculation result of the force-magnetic relation comprehensive index M, evaluating the safety state of the pipeline:

when M is more than or equal to 0.5, the risk grade is I grade and high;

when M is more than or equal to 0.36 and less than 0.5, the risk level is II level and medium level;

when M < 0.36, the risk grade is grade III, low risk grade.

2. The pipeline safety state evaluation method according to claim 1, wherein the positioning of the landslide pipeline in step S1 comprises: and determining the length of the landslide pipeline, measuring the distance of the landslide pipeline, and marking the starting point and the end point of the landslide pipeline.

3. The method according to claim 1, wherein the distance between the noncontact magnetometer and the pipe is 20 times or less the outer diameter of the pipe.

4. The pipe safety state evaluation method according to claim 1, wherein the noncontact magnetometer advances at a speed of 0.5m/s or more and 1.0m/s or less.

5. The method for evaluating a safety state of a pipeline according to claim 1, wherein in the step S2, when performing the magnetic detection, the detection is performed along the axial direction of the pipeline, and the detection length is the sum of the distance between the start point and the end point of the landslide pipeline, the threshold margin before the pipeline section, and the threshold margin after the pipeline section.

6. The pipe safety state evaluation method according to any one of claims 1 to 5, wherein the force-magnetic relationship comprehensive index M is calculated by:

in the formula:

m is a force-magnetic relation comprehensive index and is dimensionless;

Δ B is the magnetic induction variation modulus, nT;

B_Sthe initial value of the magnetic induction, nT.

7. A safe reproduction method of a stepped boosting pipeline is characterized by comprising the following steps:

s10: the pipe safety state evaluation method according to any one of claims 1 to 6, wherein the evaluation of the pipe safety state:

if the M-index distribution result is level iii, the pipeline pressure of the produced pipeline is calculated according to the following formula, and the process proceeds to step S50:

P_S＝1.06P_W+(0.95P_D-1.06P_W)·(1-M_max) (2)

in the formula:

P_Sthe pressure is the safe reproduction pressure of the pipeline, and is MPa;

P_Wis the pipeline operating pressure, MPa;

P_Ddesigning pressure, MPa, for the pipeline;

M_maxthe maximum value of the force-magnetic relation comprehensive index is dimensionless;

if the result of M index distribution is I level or II level, the step S20 is entered;

s20: excavating a measuring point with the M index being more than or equal to 0.36, and releasing stress;

s30: evaluating the pipeline safety state by adopting the same pipeline safety state evaluation method in the step S10, and comparing the M index calculated by the evaluation with the M index in the step S10:

if the M index of the excavation point is not reduced, reinforcing the pipeline by adopting an epoxy sleeve repairing technology, and recovering the normal pressure-bearing capacity of the pipeline;

if the M index of the excavation point is reduced, calculating the pipeline reproduction pressure according to the following formula:

when M is_maxWhen the ratio is more than or equal to 0.7:

P_S＝0.9P_W+0.1P_W·(1-M_max) (3)

when M is more than or equal to 0.5_maxAt < 0.7:

P_S＝0.9P_W+0.05P_W·(1-M_max) (4)

when 0.36 is less than or equal to M_maxAt < 0.5:

P_S＝1.01P_W+0.05P_W·(1-M_max) (5)

when M is_max< 0.36:

P_S＝1.06P_W+(0.95P_D-1.06P_W)·(1-M_max) (2)

s40: backfilling earthwork;

s50: and performing pipeline reproduction by adopting a stepped boosting mode according to the pipeline reproduction pressure.

8. The safe reproduction method of the stepped boosting pipeline according to claim 7, characterized in that the stepped boosting specifically comprises the following sub-steps:

s51: boosting the pressure of the pipeline by times, wherein the pressure is boosted by 1/xP every time_SWherein x is a natural number greater than or equal to 2, and after each boosting, the pipeline safety state is evaluated by the same pipeline safety state evaluation method in step S10:

if M is greater than or equal to 0.5, the process goes to step S52;

if M is less than 0.5, the voltage is continuously increased by 1/xP_SRepeating the above steps until the voltage is increased to P_SWhen the temperature of the water is higher than the set temperature,

if M is greater than or equal to 0.5, the process goes to step S52;

if M is less than 0.5, then P_SNamely the actual safe overproduction pressure P of the pipeline_TS；

S52: the pipeline is depressurized by times, and the pressure is reduced by 1/yP each time_SWherein y is a natural number more than or equal to 2, y is more than x, and after each depressurization, the pipeline safety state is evaluated by adopting the same pipeline safety state evaluation method in the step S10 until M is less than 0.5, and the pressure is the actual safe reproduction pressure P of the pipeline at the moment_TS。

9. The safe reproduction method of stepped boost pipes according to claim 8, characterised in that y-x²。

10. The safe production method of the stepped boost pipeline according to claim 8 or 9, wherein x is any value of 3, 4, 5, 6, 7, 8, 9, 10.

Technical Field

The invention relates to the technical field of pipeline safety, in particular to a pipeline safety state evaluation method and a stepped boosting pipeline safety reproduction method.

Background

In the coupling relation of taking geological disasters such as landslide as a disaster causing body and taking a long oil and gas transmission pipeline as a disaster bearing body, pipeline accidents caused by landslide frequently occur, particularly in western regions with rich oil and gas resources in China. The lighter can make the pipeline hang over the air, and the heavier can make the pipeline break. A line leak or rupture not only immediately leads to a fire and explosion, but also has a long-term impact on the environment.

Along with the vigorous laying of oil and gas pipelines and the high-speed development of numerical simulation methods in China, numerical simulation is widely applied to the domestic research of the problem of pipe-soil nonlinear contact. For landslide pipeline problems, at present, a finite element numerical simulation method is mainly adopted for research in China, common finite element analysis software comprises ANSYS, ABQUS, CEASERII, FLAC3D and the like, corresponding physical models and mathematical models are established through the finite element analysis software, boundary conditions and initial conditions of the models are set, pipeline stress distribution is obtained through simulation calculation, pipeline stress concentration positions are found, and then the safety state of the pipeline can be analyzed and evaluated, so that the subsequent repeated production operation work is guided.

However, in the prior art, when numerical simulation is performed, the setting of the boundary conditions is artificially simplified, so that the simulation conditions and the actual engineering results are greatly different. The numerical simulation method cannot accurately find the stress concentration position of the landslide pipeline, so that the safe reproduction pressure of the pipeline cannot be calculated, the reproduction operation work of the pipeline cannot be guided, and accidents such as pipe explosion, pipe breakage and the like occur in the reproduction process.

Disclosure of Invention

In view of the above problems, the present invention aims to provide a pipeline safety state evaluation method and a stepped pressure-boosting pipeline safety overproduction method, by which a stress concentration position of a landslide pipeline can be accurately found to evaluate a safety state of the pipeline, and based on the evaluation of the pipeline safety state, a pipeline safety overproduction pressure can be calculated to guide the overproduction operation work of the pipeline.

The technical scheme of the invention is as follows:

in one aspect, a method for evaluating the safety state of a pipeline is provided, which comprises the following steps:

s1: stopping conveying the pipeline, performing reconnaissance, and positioning the landslide pipeline;

s2: performing magnetic detection on the landslide pipeline through a non-contact magnetometer, and observing and recording magnetic signal data along the landslide pipeline by using software matched with the non-contact magnetometer;

s3: calculating the comprehensive index M distribution of the pipeline along the linear force-magnetic relation according to the magnetic signal data;

s4: evaluating the safety state of the pipeline according to the calculation result of the force-magnetic relation comprehensive index M;

when M is more than or equal to 0.5, the risk grade is I grade and high;

when M is more than or equal to 0.36 and less than 0.5, the risk level is II level and medium level;

when M < 0.36, the risk grade is grade III, low risk grade.

Further, the positioning the landslide pipeline in step S1 includes: and determining the length of the landslide pipeline, measuring the distance of the landslide pipeline, and marking the starting point and the end point of the landslide pipeline.

Further, the distance between the non-contact magnetometer and the pipeline is less than or equal to 20 times of the outer diameter of the pipeline.

Further, the contactless magnetometer advances at a speed of 0.5m/s or more and 1.0m/s or less.

Further, when the magnetic detection is performed in step S2, the detection is performed along the pipeline axial direction, and the detection length is the sum of the distance between the start point and the end point of the landslide pipeline, the threshold remaining amount before the pipeline section, and the threshold remaining amount after the pipeline section.

Further, the calculation method of the force-magnetic relationship comprehensive index M comprises the following steps:

in the formula:

m is a force-magnetic relation comprehensive index and is dimensionless;

Δ B is the magnetic induction variation modulus, nT;

B_Sthe initial value of the magnetic induction, nT.

On the other hand, the safe production recovery method of the stepped boosting pipeline comprises the following steps:

s10: according to any one of the above methods for evaluating the safety state of a pipeline, the method for evaluating the safety state of a pipeline comprises:

if the M-index distribution result is level iii, the pipeline pressure of the produced pipeline is calculated according to the following formula, and the process proceeds to step S50:

P_S＝1.06P_W+(0.95P_D-1.06P_W)·(1-M_max) (2)

in the formula:

P_Sthe pressure is the safe reproduction pressure of the pipeline, and is MPa;

P_Wis the pipeline operating pressure, MPa;

P_Ddesigning pressure, MPa, for the pipeline;

M_maxthe maximum value of the force-magnetic relation comprehensive index is dimensionless;

if the result of M index distribution is I level or II level, the step S20 is entered;

s20: excavating a measuring point with the M index being more than or equal to 0.36, and releasing stress;

s30: evaluating the pipeline safety state by adopting the same pipeline safety state evaluation method in the step S10, and comparing the M index calculated by the evaluation with the M index in the step S10:

if the M index of the excavation point is not reduced, reinforcing the pipeline by adopting an epoxy sleeve repairing technology, and recovering the normal pressure-bearing capacity of the pipeline;

if the M index of the excavation point is reduced, calculating the pipeline reproduction pressure according to the following formula:

when M is_maxWhen the ratio is more than or equal to 0.7:

P_S＝0.9P_W+0.1P_W·(1-M_max) (3)

when M is more than or equal to 0.5_maxAt < 0.7:

P_S＝0.9P_W+0.05P_W·(1-M_max) (4)

when 0.36 is less than or equal to M_maxAt < 0.5:

P_S＝1.01P_W+0.05P_W·(1-M_max) (5)

when M is_max< 0.36:

P_S＝1.06P_W+(0.95P_D-1.06P_W)·(1-M_max) (2)

s40: backfilling earthwork;

s50: and performing pipeline reproduction by adopting a stepped boosting mode according to the pipeline reproduction pressure.

Further, the step-wise boosting specifically comprises the following sub-steps:

s51: boosting the pressure of the pipeline by times, wherein the pressure is boosted by 1/xP every time_SWherein x is a natural number greater than or equal to 2, and after each boosting, the pipeline safety state is evaluated by the same pipeline safety state evaluation method in step S10:

if M is greater than or equal to 0.5, the process goes to step S52;

if M is less than 0.5, the voltage is continuously increased by 1/xP_SRepeating the above steps until the voltage is increased to P_SWhen the temperature of the water is higher than the set temperature,

if M is greater than or equal to 0.5, the process goes to step S52;

if M is less than 0.5, then P_SNamely the actual safe overproduction pressure P of the pipeline_TS；

S52: the pipeline is depressurized by times, and the pressure is reduced by 1/yP each time_SWherein y is a natural number more than or equal to 2, y is more than x, and after each depressurization, the pipeline safety state is evaluated by adopting the same pipeline safety state evaluation method in the step S10 until M is less than 0.5, and the pressure is the actual safe reproduction pressure P of the pipeline at the moment_TS。

Further, y ═ x²。

Further, x is any value of 3, 4, 5, 6, 7, 8, 9, 10.

Compared with the prior art, the invention has the following advantages:

the method is simple to operate and short in time consumption, and the stress concentration position of the landslide pipeline can be accurately detected by the non-contact magnetometer under the condition that the pipeline is not excavated; the safety state of the pipeline can be accurately evaluated through the force-magnetic relation comprehensive index M; the safe compound production pressure of the pipeline can be calculated according to the evaluation result of the safe state of the pipeline, and the safe compound production of the pipeline can be realized by adopting a stepped boosting mode according to the safe compound production pressure of the pipeline.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic diagram of the magnetic detection technique of the method for evaluating the safety state of a pipeline according to the present invention;

FIG. 2 is a schematic view of an operation flow of a safe reproduction method of a stepped booster pipeline according to an embodiment of the present invention;

FIG. 3 is a schematic illustration of the M-index distribution of landslide lines according to one embodiment;

FIG. 4 is a schematic diagram of M-index distribution of pipelines along the line after stress is released by excavating the pipeline in the embodiment of FIG. 3;

FIG. 5 shows the embodiment of FIG. 3 with the pressure in the pipe raised to 1/3P_SThe pipeline is in an M index distribution schematic diagram along the line;

FIG. 6 shows the embodiment of FIG. 3 with the pressure in the conduit raised to 2/3P_SThe pipeline is in an M index distribution schematic diagram along the line;

FIG. 7 shows the embodiment of FIG. 3 with the pipe pressurized to P_SAnd (3) the pipeline is in M-index distribution along the line.

Detailed Description

The invention is further illustrated with reference to the following figures and examples. It should be noted that, in the present application, the embodiments and the technical features of the embodiments may be combined with each other without conflict.

In one aspect, the invention provides a method for evaluating the safety state of a pipeline, which comprises the following steps:

s1: stopping conveying the pipeline, performing reconnaissance, and positioning the landslide pipeline.

In a particular embodiment, positioning the landslide duct comprises: and determining the length of the landslide pipeline, measuring the distance of the landslide pipeline, and marking the starting point and the end point of the landslide pipeline.

S2: and carrying out magnetic detection on the landslide pipeline through a non-contact magnetometer, and observing and recording magnetic signal data along the landslide pipeline by utilizing software matched with the non-contact magnetometer.

In a particular embodiment, the distance between the contactless magnetometer and the pipe is less than or equal to 20 times the outer diameter of the pipe, and the contactless magnetometer advances at a speed greater than or equal to 0.5m/s and less than or equal to 1.0 m/s.

In a specific embodiment, said contactless magnetometer is advanced at a speed equal to or greater than 0.5m/s, equal to or less than 0.7 m/s.

In another specific embodiment, said non-contact magnetometer is traveling at a speed of 0.6m/s or more and 0.8m/s or less.

In another specific embodiment, the contactless magnetometer is traveling at a constant speed of 1.0 m/s.

In a specific embodiment, when performing magnetic detection, the detection is performed along the axial direction of the pipeline, and the detection length is the sum of the distance between the starting point and the end point of the landslide pipeline, the threshold margin in front of the pipeline section and the threshold margin behind the pipeline section.

Optionally, the threshold margin before the pipe segment and the threshold margin after the pipe segment both range from 10m to 150 m.

Optionally, the threshold margin before the pipe segment is equal to the threshold margin after the pipe segment.

In a specific embodiment, the threshold margin before the pipe segment and the threshold margin after the pipe segment are both 50 m.

In another specific embodiment, the threshold margin before the pipe segment and the threshold margin after the pipe segment are both 60 m.

In another specific embodiment, the threshold margin before the pipe segment and the threshold margin after the pipe segment are both 30 m.

In another specific embodiment, the threshold margin before the pipe segment is 40m and the threshold margin after the pipe segment is 55 m.

S3: and calculating the distribution of the comprehensive indexes M of the force-magnetic relationship of the pipeline along the line according to the magnetic signal data, wherein the calculation method of the comprehensive indexes M of the force-magnetic relationship comprises the following steps:

in the formula:

m is a force-magnetic relation comprehensive index and is dimensionless;

Δ B is the magnetic induction variation modulus, nT;

B_Sthe initial value of the magnetic induction, nT.

S4: according to the calculation result of the force-magnetic relation comprehensive index M, evaluating the safety state of the pipeline:

when M is more than or equal to 0.5, the risk grade is I grade and high; at this point, immediate maintenance action is recommended.

When M is more than or equal to 0.36 and less than 0.5, the risk level is II level and medium level; at this time, the monitoring is mainly recommended and the maintenance is regularly carried out.

When M < 0.36, the risk grade is grade III, low risk grade. At the moment, the pipeline is safe and can be normally used.

In using the present invention, the technical principle of the magnetic detection is as follows:

the earth is a huge magnet, and the steel pipeline buried in the earth can be magnetized by the earth magnetic field, so that the generated magnetic field has magnetism. If a pipe buried in the soil has a defect and there is a periodically varying load pressure in the pipe. Then large internal stresses may develop at the pipe body imperfections during the pressure build-up. Due to the magnetoelastic effect of the ferromagnetic substance, under the action of stress generated inside the pipeline, the magnetic field at the defect position of the pipeline is enhanced, and a magnetic field leaking outwards is generated and is also called a leakage magnetic field. When the pressure in the pipeline is reduced, the stress at the defect part is reduced, the magnetic field at the defect part is reduced, but the magnetic field at the defect part cannot be restored to the original value due to the hysteresis effect of the ferromagnetic material, and is slightly increased compared with the original magnetic field intensity.

As shown in FIG. 1, an operator makes inspection along the pipeline axis over a pipe using a non-contact magnetometer that acquires vector data of the magnetic field. When the pipeline has stress concentration, the magnetic field of the pipeline has obvious change, and the detected data is input into the special software for magnetic chromatography detection for data processing and analysis. And finally evaluating the stress state and the risk level of the pipeline according to the change condition of the magnetic field above the pipeline and the actual condition in the field.

On the other hand, the invention also provides a safe reproduction method of the stepped boosting pipeline, which comprises the following steps:

s10: according to any one of the above methods for evaluating the safety state of a pipeline, the method for evaluating the safety state of a pipeline comprises:

if the M-index distribution result is level iii, the pipeline pressure of the produced pipeline is calculated according to the following formula, and the process proceeds to step S50:

P_S＝1.06P_W+(0.95P_D-1.06P_W)·(1-M_max) (2)

in the formula:

P_Sthe pressure is the safe reproduction pressure of the pipeline, and is MPa;

P_Wis the pipeline operating pressure, MPa;

P_Ddesigning pressure, MPa, for the pipeline;

M_maxthe maximum value of the force-magnetic relation comprehensive index is dimensionless;

if the result of M index distribution is I level or II level, the step S20 is entered;

s20: excavating a measuring point with the M index being more than or equal to 0.36, and releasing stress;

s30: evaluating the pipeline safety state by adopting the same pipeline safety state evaluation method in the step S10, and comparing the M index calculated by the evaluation with the M index in the step S10:

if the M index of the excavation point is not reduced, reinforcing the pipeline by adopting an epoxy sleeve repairing technology, and recovering the normal pressure-bearing capacity of the pipeline;

if the M index of the excavation point is reduced, calculating the pipeline reproduction pressure according to the following formula:

when M is_maxWhen the ratio is more than or equal to 0.7:

P_S＝0.9P_W+0.1P_W·(1-M_max) (3)

when M is more than or equal to 0.5_maxAt < 0.7:

P_S＝0.9P_W+0.05P_W·(1-M_max) (4)

when 0.36 is less than or equal to M_maxAt < 0.5:

P_S＝1.01P_W+0.05P_W·(1-M_max) (5)

when M is_max< 0.36:

P_S＝1.06P_W+(0.95P_D-1.06P_W)·(1-M_max) (2)

s40: backfilling earthwork;

s50: and performing pipeline reproduction by adopting a stepped boosting mode according to the pipeline reproduction pressure.

In a particular embodiment, said step-wise boosting comprises in particular the following sub-steps:

s51: boosting the pressure of the pipeline by times, wherein the pressure is boosted by 1/xP every time_SWherein x is a natural number greater than or equal to 2, and after each boosting, the pipeline safety state is evaluated by the same pipeline safety state evaluation method in step S10:

if M is greater than or equal to 0.5, the process goes to step S52;

if M is less than 0.5, the voltage is continuously increased by 1/xP_SRepeating the above steps until the voltage is increased to P_SWhen the temperature of the water is higher than the set temperature,

if M is greater than or equal to 0.5, the process goes to step S52;

if M is less than 0.5, then P_SNamely the actual safe overproduction pressure P of the pipeline_TS；

S52: the pipeline is depressurized by times, and the pressure is reduced by 1/yP each time_SWherein y is a natural number more than or equal to 2, y is more than x, and after each depressurization, the pipeline safety state is evaluated by adopting the same pipeline safety state evaluation method in the step S10 until M is less than 0.5, and the pressure is the actual safe reproduction pressure P of the pipeline at the moment_TS。

Optionally, x is equal to y²。

Optionally, x is any value of 3, 4, 5, 6, 7, 8, 9, or 10.

In a specific embodiment, x is 3 and y is 9, then the step-wise boosting specifically comprises the following sub-steps:

s51': pressure raising the pipe to 1/3P_SAnd adopting the same pipeline safety state evaluation method in the step S10 to evaluate the pipeline safety state:

if M is not less than 0.5, go to step S52';

if M is less than 0.5, go to step S53';

s52': the pipeline is depressurized for times, and the pressure is reduced by 1/9P each time_SAnd after each depressurization, adopting the same pipeline safety state evaluation method in the step S10 to evaluate the pipeline safety state until M is less than 0.5, wherein the pressure is the actual safe reproduction pressure P of the pipeline_TS；

S53': pressure raising the pipe to 2/3P_SAnd adopting the same pipeline safety state evaluation method in the step S10 to evaluate the pipeline safety state:

if M is not less than 0.5, go to step S52';

if M is less than 0.5, go to step S54';

s54': pressurizing the pipeline to P_SAnd adopting the same pipeline safety state evaluation method in the step S10 to evaluate the pipeline safety state:

if M is not less than 0.5, go to step S52';

if M is less than 0.5, then P_SNamely the actual safe overproduction pressure P of the pipeline_TS。

The operation flow of the safe reproduction method of the stepped booster pipeline of the embodiment is shown in fig. 2.

In a specific embodiment, pipeline safety state evaluation and stepped boosting are carried out on a landslide pipeline section of a large-diameter long pipeline, so that pipeline safety recovery is realized.

According to the method for evaluating the safety state of the pipeline, the large-diameter long-pipeline landslide pipe section is subjected to magnetic detection by adopting the non-contact magnetometer Grad-03-500, the magnetic signal data along the landslide pipeline is observed and recorded by utilizing the comprehensive data acquisition processor matched with the non-contact magnetometer, the distribution of the comprehensive index M of the force-magnetic relation along the line of the landslide pipeline is calculated according to the magnetic signal data, and the result is shown in figure 3. As can be seen from fig. 3, the M index of the three measuring points of the landslide section is greater than 0.36 and less than 0.5, and the risk level is level ii or medium; all M indices were below 0.5 and no test points with a risk rating of grade I were present.

And (3) according to the detection result, excavating the measuring point position with the risk level of II to release stress, and detecting by using the non-contact magnetometer again to obtain the M index of the pipeline section along the line, wherein the M index is shown in figure 4. As can be seen from fig. 4, M indexes of each point are all decreased after excavation, and the risk levels of the landslide pipe sections are all in level iii, which indicates that the pipeline stress can be effectively reduced and the stress releasing effect is significant during excavation.

Calculating the safe reproduction pressure P of the pipeline according to the M value along the pipeline of the excavated landslide pipeline_S6.80 MPa. During the operation of the compound production, a stepped boosting method is adopted, and the first stage of the pipeline is boosted to 1/3P_SThe M index of the pipe section along the line is shown in fig. 5, which is measured by a non-contact magnetometer at 2.27 MPa. As can be seen from fig. 5, in the process of the double-production operation, as the pressure of the pipeline increases, the stress of the pipeline increases, the M index along the pipeline also increases, but the risk levels of the pipeline are all in level iii, and no sudden change of stress occurs.

The pipeline continues to be pressurized to 2/3P_SThe M index of the pipe section along the line is shown in fig. 6, which is measured by a non-contact magnetometer at 4.53 MPa. As can be seen from FIG. 6, as the pressure of the pipeline rises, the M index of the pipeline along the line continues to increase, the risk levels of the pipeline are all in level III, and the situation of stress sudden change does not occur.

The pipeline is continuously boosted to the safe working pressure P of the operation of the re-production_SThe M index of the pipe section along the line is shown in fig. 7, which is measured by a non-contact magnetometer at 6.80 MPa. As can be seen from fig. 7, as the pressure of the pipeline increases, the M index along the pipeline continues to increase, the risk levels of the pipeline are all in level iii, and no sudden change of stress occurs, which indicates the safety recovery pressure P of the landslide pipeline calculated herein_SThe numerical value is real and reliable, namely the actual safe reproduced pressure P of the pipeline_TS。

In summary, when the large-diameter long-pipeline landslide pipe section is subjected to step-type pressure boosting, and the safe compound production of the pipeline is realized, the landslide pipe section does not have pipeline stress mutation in the process of fractional pressure boosting, so that the comprehensive index M of the force-magnetic relationship is not less than 0.5.

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.