8 kinds of underground pipeline detection methods

Underground pipeline engineering facilities, throughout the construction process, is an important infrastructure of the city. Its water supply, drainage, gas supply, communication cables, electricity, etc., constitute the "lifeline" of the city, and are responsible for the city's energy supply, information transmission, sewage and wastewater discharge, providing a basic guarantee for the survival and development of the city. With the increasing development of social modernization, the number of underground pipelines in the city is increasing, and the pipelines are intertwined and complex, which undoubtedly makes the underground pipeline detection more difficult.

In this paper, we analyze and study the applicability and advantages and disadvantages of various underground pipeline detection methods for the selection of underground pipeline detection construction methods

to provide reference.

1、Water supply lines

Water supply lines are divided into metal pipelines and non-metallic pipelines. Metal water supply lines can be used induction method and direct connection method to probe; non-metallic pipelines can be used to probe the PQWT non-metallic pipeline detector, or the use of brazing, excavation methods to directly determine the location and depth of the pipeline.

A. Operation method of induction method probing

First of all, you need to determine the general direction of the water supply line.

Secondly, along the general direction of the pipeline, place the transmitter of the pipeline detector, the transmitter should be placed in the same direction as the pipeline. Select the appropriate frequency (water pipeline, generally using less than 16K frequency for tracking, to determine the orientation; using more than 30K frequency for detailed probing, to determine its plane location and depth) to transmit the signal.

Finally, use the receiving instrument to receive a valid signal. The effective signal should be determined for the water pipeline by the transmitter to send a signal and produce a secondary induction magnetic field signal, in the case of transmitters and receivers are close together (according to the transmitter transmitting frequency to determine the spacing), the receiver receives a primary magnetic field signal from the transmitter, when the signal can not be used as an effective signal to determine the pipeline. According to the received effective signal for analysis, determine the location and depth of the pipeline plane.

B. The specific operation method of the direct connection method

The direct connection method is to connect the transmitter directly with the bare water pipeline, the metal water pipeline directly loaded with current, so that the pipeline and the transmitter ground line to form a current loop, generating electromagnetic fields, so that the metal water pipeline induction current after the generation of secondary magnetic fields.

As with the induction method, the receiver is used to receive the signal and the analysis determines the plane position and depth of the pipeline.

Non-metallic water supply lines can be directly detected using the PQWT non-metallic pipeline detector.

2、Communication pipeline

Communication pipeline contains telecommunications, Unicom, Netcom, mobile, Tietong and other rights unit pipeline, its burial mode is generally divided into direct burial, pipe burial and trench burial.

Underground pipeline detector transmission signal is generally better, due to its diameter are relatively small, therefore, the detection method is mainly clamp method.

Clamp method is the use of pipeline detection instrument clamping equipment, directly clamped on the telecommunications pipeline, clamping equipment itself to produce a strong annular magnetic field, so that the clamped telecommunications pipeline produces a strong induction current, thereby producing a secondary induction field.

3、Power pipeline

Power pipeline probing can generally be used to explore the industrial frequency method or clamp method.

The use of current-carrying transmission cable contains the AC current generated by the industrial frequency signal or metal pipeline induction current generated by the electromagnetic field for pipeline detection.

Industrial frequency method does not require the establishment of artificial field source, simple method, low cost, high efficiency, but the resolution is not high, the depth accuracy rate is low, for the initial detection of cable probing, in the underground pipeline blind detection is very practical.

The use of the clamp method with the use of the clamp method in the telecommunications pipeline the same method. Electricity pipeline using the clamp method signal is relatively good, the detection accuracy is relatively high, in general, fully meet the "Regulations" precision, is the main method of power pipeline detection.

4、Gas pipeline

Gas pipeline pipe diameter is generally not large, its material is divided into metal and non-metallic two.

For metal gas pipeline, we generally use the induction method to probe, pipe diameter of the thin pipeline, we can also use the clamp method to probe. The detection method as described above, for safety reasons, gas pipelines are generally not used in direct method.

For non-metallic gas pipelines, the use of PQWT non-metallic pipeline detector to solve

5 Heat pipeline

Thermal pipeline material is generally steel pipe, the instrument probing signal is better, the thermal pipe diameter change is relatively large, and its external protective material.

Thermal pipelines can generally use the direct method, induction method and clamping method to detect, and its specific operation with the above-mentioned operating process.

6、Industrial pipelines

Industrial pipelines generally include oil, acid, alkali and other pipelines, such pipelines need to pay attention to safety issues in the process of probing. This part of the pipeline material metal (such as steel, etc.) and non-metallic (such as concrete, etc.), the detection method and the same as described above, for metal pipelines generally use induction method, for non-metallic pipelines in general PQWT non-metallic pipeline detector, the instrument uses multi-frequency compound modulation acoustic vibration technology, through the installation of sound vibrators at the interface of the pipeline, in the pipeline to generate a variety of frequencies mixed with a specific acoustic signal, the signal JII page with the pipeline two-way lateral transmission and vertical transmission to the ground, through the sensor for sound acquisition, the collected signal through the receiving host processing, to visualize the spectrum and signal column on the host screen, while the sound will also be output through the host to the headphones, through the "Xin", "see" combination of two ways. "See" two ways to combine analysis to determine the location and direction of the pipeline.

7 integrated pipe trench

Comprehensive pipeline trench in general contains more complex pipelines, but also more difficult to unify the conclusion, according to the actual situation of the city sub-probe, in addition to the use of a variety of pipeline detection methods within the comprehensive pipeline trench, due to the comprehensive pipeline trench in the underground formation of a certain space, the use of PQWT non-metallic pipeline detector can be more obvious to explore its direction and depth.

8 Unknown pipeline

This kind of pipeline needs to be determined according to the actual situation, and the relevant properties of the pipeline need to be identified before probing.

Translated with www.DeepL.com/Translator (free version)