阅读说明：本技术 一种适用于砂土的全分布式管道覆土深度监测系统及方法 (Fully-distributed pipeline soil covering depth monitoring system and method suitable for sandy soil ) 是由 杨宇烨 邵翰林 史波 于 2021-01-27 设计创作，主要内容包括：本发明公开一种适用于砂土的全分布式管道覆土深度监测系统,包括管道、温度传感光缆和温度解调仪,管道埋设于土体内,在距离管道正上方10～20cm处的土体中敷设温度传感光缆,温度传感光缆沿着管道轴向全程敷设；温度解调仪与温度传感光缆的两端相连形成环路。具有安装简易、反馈即时、全覆盖监测、节约人力的特点。(The invention discloses a fully-distributed pipeline soil covering depth monitoring system suitable for sandy soil, which comprises a pipeline, a temperature sensing optical cable and a temperature demodulator, wherein the pipeline is buried in soil, the temperature sensing optical cable is laid in the soil body 10-20 cm away from the position right above the pipeline, and the temperature sensing optical cable is laid along the axial direction of the pipeline in the whole process; the temperature demodulator is connected with two ends of the temperature sensing optical cable to form a loop. The device has the characteristics of simple installation, instant feedback, full-coverage monitoring and labor saving.)

1. The utility model provides a full distributed pipeline earthing depth monitoring system suitable for sand, its characterized in that: the temperature sensing optical cable is laid in a soil body 10-20 cm away from the right upper part of the pipeline, and the temperature sensing optical cable is laid along the axial direction of the pipeline in the whole process; the temperature demodulator is connected with two ends of the temperature sensing optical cable to form a loop.

2. The fully-distributed pipe casing depth monitoring system suitable for sandy soil according to claim 1, wherein: the temperature sensing optical cable adopts a communication optical cable which comprises an optical fiber and a protective layer wrapped on the periphery of the optical fiber.

3. The fully-distributed pipe casing depth monitoring system suitable for sandy soil according to claim 1, wherein: the temperature sensing optical cable loop is integrated in the composite optical cable; the composite optical cable and the pipeline are both embedded in the soil body, and the composite optical cable is located right above the pipeline.

4. A monitoring method of the fully distributed pipe casing depth monitoring system suitable for sandy soil according to any one of claims 1 to 3, wherein the monitoring method comprises the following steps: the method comprises the following steps:

s1, installing a pipeline, a temperature sensing optical cable and a temperature demodulator;

s2, starting a temperature demodulator, generating a temperature-hour curve of the measured soil body in real time, and obtaining the following formula (1) according to the change rule of the temperature at a certain position in the soil body along with time:

t (z, T) ═ T (z) + a (z) sin (ω T + ψ (z)) formula (1)

Wherein T (z, T) is a soil body temperature value when the burial depth z is at T, z is the actual burying depth of the temperature sensing optical cable, T (z) is the average temperature of the soil body at z, A (z) is the amplitude at z, T is time, omega is the frequency at z, and psi is the initial phase at z;

s3, obtaining corresponding amplitude according to the temperature-hour curve of the sandy soil, and judging the depth of a soil body at a certain position according to the relation between the amplitude and the monitoring embedding depth of the temperature sensing optical cable;

wherein, the fitting formula of the temperature-hour curve amplitude and the depth of the sandy soil is as follows:

y ═ 0.148ln (a (z)) +0.3397 formula (2)

Wherein A (z) is the amplitude of the temperature-hour curve of the sandy soil, and y is the monitoring burying depth of the temperature sensing optical cable, namely the corresponding covering depth of the sandy soil;

and S4, if the embedding depth y obtained in the step S3 exceeds a preset threshold value, an alarm is sent to a valve chamber personnel through a temperature demodulator.

Technical Field

The invention belongs to geological monitoring technology, and particularly relates to a fully-distributed pipeline soil covering depth monitoring system and method suitable for sandy soil.

Background

In pipeline engineering, ensuring the integrity of pipelines to prevent oil and gas loss due to leakage and severe contamination of high-consequence areas are important factors to consider. The determination of the buried depth of the pipeline is of great significance for preventing leakage, and whether natural erosion or artificial excavation is adopted, the covering soil on the surface of the pipeline is thinned, so that the surface of the pipeline is exposed easily, and the leakage is caused by environmental corrosion. And for sandy soils, it is more susceptible to erosion than other soils. At present, in the aspect of monitoring the thickness of a covering layer on the surface of a pipeline, a method of manually inspecting and adopting sand marking poles in important areas is mainly adopted in the industry, but both methods are difficult to achieve real full-coverage monitoring, and have certain time lag because of the need of on-site confirmation of personnel. The manual inspection usually requires that the pipeline is partially exposed in a certain area to find problems, and the thinning of the pipeline covering soil protective layer is difficult to identify.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to solve the defects in the prior art, provides a full-distributed pipeline soil covering depth monitoring system and method suitable for sandy soil, and has the characteristics of simplicity and easiness in installation, instant feedback, full-coverage monitoring and labor saving.

The technical scheme is as follows: the invention provides a fully-distributed pipeline soil covering depth monitoring system suitable for sandy soil, which comprises a pipeline, a temperature sensing optical cable and a temperature demodulator, wherein the pipeline is buried in soil, the temperature sensing optical cable is laid in the soil body 10-20 cm away from the position right above the pipeline, and the temperature sensing optical cable is laid along the axial direction of the pipeline in the whole course; the temperature demodulator is connected with two ends of the temperature sensing optical cable to form a loop.

Furthermore, the temperature sensing optical cable adopts a communication optical cable which comprises an optical fiber and a protective layer wrapped on the periphery of the optical fiber.

Further, the temperature sensing optical cable loop is integrated in the composite optical cable; the composite optical cable and the pipeline are both embedded in the soil body, and the composite optical cable is located right above the pipeline. The temperature sensing optical cable is integrated in the protective sleeve at the periphery of the composite optical cable, so that the capability of resisting environmental erosion and external force of the temperature sensing optical cable is improved, and inspection and maintenance are facilitated.

The invention also discloses a monitoring method of the fully-distributed pipeline soil covering depth monitoring system suitable for sandy soil, which comprises the following steps:

s1, installing a pipeline, a temperature sensing optical cable and a temperature demodulator;

s2, starting a temperature demodulator, generating a temperature-hour curve of the measured soil body in real time, and obtaining the following formula (1) according to the change rule of the temperature at a certain position in the soil body along with time:

t (z, T) ═ T (z) + a (z) sin (ω T + ψ (z)) formula (1)

Wherein T (z, T) is a soil body temperature value when the burial depth z is at T, z is the actual burying depth of the temperature sensing optical cable, T (z) is the average temperature of the soil body at z, A (z) is the amplitude at z, T is time, omega is the frequency at z, and psi is the initial phase at z;

s3, obtaining corresponding amplitude according to the temperature-hour curve of the sandy soil, and judging the depth of a soil body at a certain position according to the relation between the amplitude and the monitoring embedding depth of the temperature sensing optical cable;

wherein, the fitting formula of the temperature-hour curve amplitude and the depth of the sandy soil is as follows:

y ═ 0.148ln (a (z)) +0.3397 formula (2)

Wherein A (z) is the amplitude of the temperature-hour curve of the sandy soil, and y is the monitoring burying depth of the temperature sensing optical cable, namely the corresponding covering depth of the sandy soil;

and S4, if the burying depth z obtained in the step S3 exceeds a preset threshold value, an alarm is sent to a valve chamber personnel through a temperature demodulator.

Has the advantages that: compared with the prior art, the invention has the following advantages:

(1) the monitoring system only needs the temperature sensing optical cable and the temperature demodulator, and has the advantages of exquisite structure, simple installation, convenient maintenance and low cost;

(2) the temperature is represented by using the change of the physical quantity of the transmission light in the temperature sensing optical cable, so that the information can be transmitted immediately;

(3) the optical cable is buried along the whole length of the pipeline, so that the whole-process monitoring of the pipeline engineering can be realized;

(4) the invention transmits the relevant temperature information to the corresponding valve chamber, and only the staffs need to be stationed in the valve chamber without arranging patrol staffs.

Drawings

FIG. 1 is a schematic overall structure diagram according to an embodiment of the present invention;

FIG. 2 is a schematic diagram illustrating the relative positioning of the temperature sensing cables and the pipeline in accordance with an embodiment of the present invention;

fig. 3 is a graph of temperature versus hours for different burial depths in the sand in an embodiment of the invention.

Detailed Description

The technical solution of the present invention is described in detail below, but the scope of the present invention is not limited to the embodiments.

As shown in fig. 1 and 2, the fully-distributed pipeline covering depth monitoring system suitable for sandy soil comprises a pipeline 1, a temperature sensing optical cable 2 and a temperature demodulator 3, wherein the pipeline 1 is buried in a soil body, the temperature sensing optical cable 2 is laid in a soil body 10-20 cm away from the position right above the pipeline 1, and the temperature sensing optical cable 2 is laid along the axial direction of the pipeline in the whole process; the temperature demodulator 3 is connected with two ends of the temperature sensing optical cable 2 to form a loop, and the temperature demodulator 3 collects the soil body temperature at the buried position through the temperature sensing optical cable 2.

The burying depth (10-20 cm, for example, 15cm) of the temperature sensing optical cable 2 can accurately test the soil covering depth above the pipeline 1 to the maximum extent, and once the temperature sensing optical cable 2 is exposed outside sandy soil, the temperature sensing optical cable means that a worker needs to check and maintain the temperature sensing optical cable.

The temperature sensing optical cable 2 is a communication optical cable which comprises an optical fiber and a protective layer wrapped on the periphery of the optical fiber.

In order to ensure the data accuracy of the monitoring system during operation, the temperature sensing optical cable 2 in the embodiment is integrated in the composite optical cable 4 in a loop way; the composite optical cable 4 and the pipeline 1 are both embedded in the soil, and the composite optical cable 4 is positioned right above the pipeline 1.

The monitoring method of the distributed pipeline 1 soil covering depth monitoring system comprises the following steps:

s1, installing the pipeline 1, the temperature sensing optical cable 2 and the temperature demodulator 3;

s2, starting the temperature demodulator 3, generating a temperature-hour curve of the measured soil body in real time, wherein the change rule of the temperature at a certain position in the soil body along with time is known to be approximate to a sine function of the following formula:

the formula is T (z, T) ═ T (z) + A (z) sin (ω T + ψ (z)) formula (1)

Wherein T (z, T) is a soil body temperature value when the burial depth z is at T, z is the actual burying depth of the temperature sensing optical cable, T (z) is the average temperature of the soil body at z, A (z) is the amplitude at z, T is time, omega is the frequency at z, and psi is the initial phase at z;

s3, obtaining corresponding amplitude according to the temperature-hour curve of the sandy soil, and judging the depth of a soil body at a certain position according to the relation between the amplitude and the monitoring embedding depth of the temperature sensing optical cable;

wherein, the fitting formula of the temperature-hour curve amplitude and the depth of the sandy soil is as follows:

y ═ 0.148ln (a (z)) +0.3397 formula (2)

Wherein A (z) is the amplitude of the temperature-hour curve of the sandy soil, and y is the monitoring burying depth of the temperature sensing optical cable, namely the corresponding covering depth of the sandy soil.

Example (b):

in this embodiment, the soil body embedded in the pipeline 1 and the temperature sensing optical cable 2 is sandy soil.

It is known that optical cables are usually buried in ditches with uniform soil conditions in pipe works, when there is no external heat source or sink to amplitude a_(z)In the case of influence, as shown in fig. 3, when the buried depth of the pipeline 1 is less than 50cm, the temperature-hour curve of the soil body shows a significant periodic variation, and the amplitude thereof decreases with the increase of the buried depth until the amplitude of the curve is substantially zero when the buried depth of the pipeline 1 is more than 50 cm.

In this embodiment, through the tests performed on the sandy soil, the amplitude-depth corresponding data of the temperature-hour curve of the sandy soil can be obtained as shown in table 1.

TABLE 1 correlation of temperature-hour curve amplitude-depth of sandy soil

Amplitude size (. degree. C.)	Sand coverage depth (m)
		7.5	0
2.5	0.2
		0.5	0.5
0	1

Therefore, the depth of a soil body at a certain position can be quantitatively judged according to the relation between the amplitude and the depth of the soil body temperature-hour curve of the sandy soil.