A trenchless geophysical exploration method for compensator locations of buried heating pipelines

Abstract

The present invention provides a trenchless geophysical exploration method for determining the location of a compensator for a directly buried heating pipeline, comprising the following steps: Step 1: Using a weak magnetic detection device, measure the magnetic field strength along the water supply pipe and return pipe of the directly buried heating pipeline, respectively, to obtain a water supply pipe magnetic field strength curve and a return pipe magnetic field strength curve; the horizontal axis represents the measured distance value, and the vertical axis represents the magnetic field strength value perpendicular to the ground; Step 2: Find characteristic waveforms from the water supply pipe magnetic field strength curve and the return pipe magnetic field strength curve, respectively; the characteristic waveform of the water supply pipe is W-shaped, and the characteristic waveform of the return pipe is U-shaped or V-shaped; Step 3: If the measured distance value of the characteristic waveform of the return pipe is within the range of the measured distance value of the characteristic waveform of the water supply pipe, then determine that the location at the measured distance value is the location of the compensator. The present invention can accurately determine the installation location of the compensator based on the characteristic patterns. The present invention is a trenchless geophysical exploration method that does not require road excavation, is time-saving, and is low-cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of trenchless geophysical exploration of accessories for directly buried heating pipelines, and in particular relates to a trenchless geophysical exploration method for compensator positions of directly buried heating pipelines. Background Art

[0002] Winter heating in northern my country is provided by centralized heating, and direct buried heating pipelines are a common method of laying pipes in the primary network of urban heating systems. In addition to pipelines, direct buried heating pipelines also need to install accessories, including compensators, fixed piers and valves. The primary network of the urban heating system provides heating in winter, and the temperature of the water supply pipe is generally 95-135 degrees Celsius, and the temperature of the return pipe is generally 30-40 degrees Celsius. There is no heating in summer, and the temperature of the water supply pipe and return pipe is generally 15 degrees Celsius. The temperature difference will cause changes in the expansion and contraction of the pipe. In order to prevent the pipe from cracking, compensators need to be installed. Compensators are divided into two types: corrugated and sleeve. Their materials are mainly stainless steel. According to custom, a compensator is installed every 50 meters. In order to prevent the creep effect of the pipeline, fixed piers need to be installed on the pipeline. According to custom, one is also installed every 50 meters.

[0003] Accessories require regular inspection and replacement. Valves are typically installed in hand wells, making their locations easily identifiable. Compensators and anchoring piers are buried along with the pipeline. Limited early construction technology and significant changes in the urban surface have resulted in a lack of early pipeline data, making it difficult to determine the exact location of the compensators. Excavating the entire pipeline route also presents challenges of long construction times and high costs. Summary of the Invention

[0004] In response to the technical problem in the prior art that it is difficult to determine the exact buried position of the compensator, the present invention provides a trenchless geophysical exploration method for the compensator position of a directly buried heating pipeline. According to the characteristics that the directly buried heating pipeline is made of ferromagnetic materials and the compensator is made of non-ferromagnetic materials, weak magnetic detection technology is used to accurately locate the buried position of the compensator without excavation.

[0005] The technical solution adopted by the present invention is: a trenchless geophysical exploration method for the compensator position of a directly buried heating pipeline, comprising the following steps:

[0006] Step 1: Use a weak magnetic detection device to measure the magnetic field strength along the water supply pipe and return pipe of the direct buried heating pipeline, and obtain a water supply pipe magnetic field strength curve graph and a return pipe magnetic field strength curve graph. The horizontal axis of the two curves is the measured distance value, and the vertical axis is the magnetic field strength value perpendicular to the ground.

[0007] Step 2: Find the characteristic waveforms from the magnetic field intensity curves of the water supply pipe and the return pipe respectively. The characteristic waveform of the water supply pipe is W-shaped, and the characteristic waveform of the return pipe is U-shaped or V-shaped.

[0008] Step 3: If the measured distance value of the characteristic waveform of the return pipe is within the range of the measured distance value of the characteristic waveform of the supply pipe, it is determined that the measured distance value is the position of the compensator.

[0009] Furthermore, the measuring distance is not less than 50 meters.

[0010] Working Principle: The supply and return pipes of the direct buried heating pipeline are generally made of iron pipes, which are ferromagnetic materials. The material of the compensator is mainly stainless steel, which is a non-ferromagnetic material. Therefore, the magnetic field strength at the two locations is different, and the magnetic field strength at the compensator is smaller than that of the supply and return pipes. The compensator on the supply pipe is longer, and its magnetic field strength waveform is W-shaped. The compensator on the return pipe is relatively shorter, and depending on the actual length, the magnetic field strength waveform is U-shaped or V-shaped. According to custom, the compensators on the supply and return pipes are installed in pairs at the same location. Therefore, by comparing the positions of the two waveforms, the installation position of the compensator can be determined.

[0011] Compared with the existing technology, the beneficial effects of the present invention are: the present invention adopts a non-excavation geophysical exploration method, uses weak magnetic detection equipment, travels along the heating pipeline on the ground, detects the magnetic field strength value perpendicular to the ground, and can accurately determine the installation position of the compensator based on the characteristic pattern, without the need to excavate the road surface, saving time and low cost; and can eliminate the influence of objects such as crossed pipes, with a positioning accuracy rate of over 99%. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a flow chart of an embodiment of the present invention;

[0013] Figure 2 This is a curve diagram of the magnetic field strength of the water supply pipe according to an embodiment of the present invention;

[0014] Figure 3 This is a curve diagram of the magnetic field strength of the return pipe of an embodiment of the present invention. DETAILED DESCRIPTION

[0015] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0016] The embodiment of the present invention provides a trenchless geophysical exploration method for compensator positions of direct buried heating pipelines, such as Figure 1 As shown, it includes the following steps:

[0017] Step 1: Use weak magnetic detection equipment to measure the magnetic field strength along the water supply pipe and return pipe of the direct buried heating pipeline. The measurement distance of the water supply pipe and return pipe is 50 meters. The weak magnetic detection equipment has four groups of probes, three in each group, which detect the magnetic field strength of the X-axis, Y-axis and Z-axis respectively. The Z-axis is perpendicular to the ground, the X-axis is the direction along the pipeline, and the Y-axis is perpendicular to the pipeline. Set the measured distance value as the horizontal coordinate and the magnetic field strength value perpendicular to the ground as the vertical coordinate to obtain the magnetic field strength curve of the water supply pipe and the magnetic field strength curve of the return pipe, as shown below. Figure 2 and Figure 3 shown.

[0018] Step 2: Find the W-shaped characteristic waveform from the magnetic field strength curve of the water supply pipe, and then find the U-shaped or V-shaped characteristic waveform from the magnetic field strength curve of the return pipe. When the compensator on the return pipe is long, the waveform of its magnetic field strength is U-shaped, and when it is short, the waveform of its magnetic field strength is V-shaped. In this embodiment, Figure 2 In the figure, a W-shaped characteristic waveform appeared at a position near the measurement distance of 21-27 meters; Figure 3 In the figure, a U-shaped characteristic waveform appears at a position where the measured distance value is around 22-26 meters.

[0019] Step 3: If the measured distance value of the return pipe characteristic waveform is within the range of the measured distance value of the supply pipe characteristic waveform, the compensator is determined to be located at that measured distance value. That is, the compensator location on the supply pipe falls within the measured distance value range corresponding to the W-shaped characteristic waveform; the compensator location on the return pipe falls within the measured distance value range corresponding to the U-shaped or V-shaped characteristic waveform.

[0020] This embodiment utilizes trenchless geophysical exploration, eliminating the need for excavation to accurately locate the compensator position, unaffected by interfering objects such as intersecting pipes and metal ground stakes. Interfering objects produce identical fluctuations in the magnetic field intensity curves for both the supply and return pipes, and do not form a U-shaped or V-shaped characteristic waveform corresponding to a W-shaped waveform at the same measured distance.

[0021] The present invention has been described in detail above through the embodiments, but the contents described are only exemplary embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. The scope of protection of the present invention is defined by the claims. Any use of the technical solution described in the present invention, or any person skilled in the art who, inspired by the technical solution of the present invention, designs a similar technical solution within the essence and scope of protection of the present invention to achieve the above-mentioned technical effects, or any equivalent changes and improvements made to the scope of application, shall still fall within the scope of protection covered by the patent of the present invention.

Claims

1. A trenchless geophysical exploration method for the compensator position of a directly buried heating pipeline, characterized by: The following steps are involved: Step 1: Use a weak magnetic detection device to measure the magnetic field strength along the water supply pipe and return pipe of the direct buried heating pipeline, and obtain a water supply pipe magnetic field strength curve graph and a return pipe magnetic field strength curve graph. The horizontal axis of the two curves is the measured distance value, and the vertical axis is the magnetic field strength value perpendicular to the ground. Step 2: Find the characteristic waveforms from the magnetic field intensity curves of the water supply pipe and the return pipe respectively. The characteristic waveform of the water supply pipe is W-shaped, and the characteristic waveform of the return pipe is U-shaped or V-shaped. Step 3: If the measured distance value of the characteristic waveform of the return pipe is within the range of the measured distance value of the characteristic waveform of the supply pipe, it is determined that the measured distance value is the position of the compensator.

2. The trenchless geophysical exploration method for compensator locations of directly buried heating pipelines according to claim 1, characterized in that: The measuring distance is not less than 50 meters.

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