Based on the construction characteristics of natural gas pipeline, this paper analyzes and discusses in detail the problems existing in the construction process of natural gas pipeline and the corresponding solutions for reference.

Keywords: natural gas; Pipeline construction; Problems; measure

1 preface

As a clean and environmentally friendly new energy, natural gas contributes to the sustainable development of China's economy. Therefore, the construction quality management of natural gas pipeline project is very important, and the problems in the construction process should be found in time to ensure the smooth implementation of the project.

2 Construction characteristics of natural gas pipeline project

2. The1project has strong concealment.

Due to many factors, urban natural gas pipelines are generally laid underground, so the pipeline laying project has certain concealment. It is precisely because of this concealment that it brings some difficulties to the pipeline construction process, and only the surface can be detected in the later maintenance and inspection process, which may easily lead to some safety hazards and even lead to various serious phenomena such as gas leakage.

2.2 It is difficult to check during construction.

Because most natural gas pipelines are underground, it is difficult to carry out detailed and intuitive inspection after the project is completed. However, the quality of natural gas pipeline can not be judged only by appearance, and it is very difficult to detect the inside of the pipeline, which is easy to bury certain security risks for the quality of the pipeline.

2.3 There are many factors that affect the construction.

In the process of natural gas pipeline construction, its construction quality will be affected by various factors. Including the pre-design link, material preparation link, the selection of construction equipment and the specific environment of the construction site. , will have a certain impact on the quality of pipeline construction.

3 problems in the construction of urban natural gas pipelines

3. 1 Trench excavation and backfilling

Trench excavation and backfilling are important construction links in natural gas pipeline construction. For example, in construction, if the trench excavation depth and trench foundation are not firm enough, once backfilled and compacted by large machinery, it is easy to bend and deform the pipeline. In the process of laying natural gas pipelines, construction is sometimes carried out in places with relatively high groundwater level. If the drainage pipeline is not laid in time in this part of the area, the lower part of the pipeline may be suspended after a period of time, and the compaction is not strict during construction, which will easily lead to the arching deformation of the pipeline. Backfilling is a common problem in natural gas construction. Backfill soil does not meet the construction standards, and the soil contains hard stones, which is easy to damage the pipeline. In addition, if the height of backfill and the quality of compaction are not controlled within the standard range, the laying depth of natural gas pipeline construction will not reach the construction standard, resulting in problems such as false trench foundation and deformation of natural gas pipeline.

3.2 coating repair and repair problems.

In the construction of natural gas pipeline, the problem of anticorrosive coating is also a frequent problem. This problem is mainly manifested in the rough surface of the anticorrosive coating of natural gas pipeline, which does not meet the standards required for construction and has a certain impact on the construction quality. If the length of anti-corrosion lap joint treatment is not enough or lap joint is not timely, it will leave hidden dangers. In addition, when repairing the rotten layer, the repaired area does not meet the relevant construction standards, and the adhesive used for repairing is insufficient, which will damage the anticorrosive layer again. In the construction of natural gas pipeline, the quality of joint coating will affect the anticorrosion ability of pipeline.

3.3 Welding quality problems

In natural gas engineering construction, welding is the most important construction technology, and welding quality is also a common problem in natural gas construction in China. The main problems in construction welding are slag inclusion, welding burr, blowhole and crack, which seriously affect the welding quality and lay a safety hazard for natural gas pipeline construction. Quality problems often occur in natural gas welding, and because quality defects are not easy to be found in construction, welding quality problems always exist in natural gas pipeline engineering construction. Because of the concealment of welding defects, it is difficult to repair the pipeline after it is put into use. Therefore, once there is a problem, it will lead to large-scale gas stoppage and maintenance, and in serious cases, it will lead to large-scale pipeline replacement, which will not only have a bad impact on society, but also greatly increase the construction cost of the construction unit.

4 natural gas pipeline construction problems and solutions

4. 1 Strengthen the quality management of natural gas pipeline raw materials

In the urban natural gas pipeline construction, the quality of the pipeline plays a decisive role, which is related to the construction quality of the whole project, so it is of great significance to strengthen the quality management of raw materials in the project construction. Before construction, strengthen the supervision of raw material procurement and storage, and make reasonable control from raw material suppliers to production and selection, so as to make raw materials meet technical standards and provide high-quality raw materials for pipeline construction. The raw materials needed for the project are an important standard to determine the construction quality. Therefore, the inspection of raw materials should be done well in the construction, and diversified and systematic inspection methods should be adopted to ensure the final quality of materials and provide safety guarantee for the construction of natural gas pipeline projects.

4.2 Strengthen the optimization of pipeline welding

At present, China's welding technology can fully meet the welding quality requirements of natural gas pipelines. In the concrete construction process, the downward welding method is generally used to weld the pipeline, and the welding process parameters with large blunt edge and small gap are adopted. The height and width of the weld should be smaller than the upward weld. This welding technology is not only less difficult to construct, but also less influenced by external factors, so it can effectively control the welding quality. When using this welding technology to weld natural gas pipeline, the thickness of each layer of weld should be controlled at about 2 mm, and the number of welded joints should be reduced as much as possible, so that the welded pipeline is more beautiful and the related pipeline quality problems caused by too many welding cracks can be effectively avoided.

4.3 Strengthen pipeline anticorrosion technology

Natural gas pipelines are particularly prone to corrosion, so to some extent, the anti-corrosion effect of pipelines directly determines the service life of pipelines, and also has a great impact on the safety performance of pipelines, especially when passing through some relatively densely populated areas, it is necessary to ensure the safety of natural gas pipeline construction in order to better protect people's lives and property. When optimizing the anticorrosion technology of natural gas pipeline, we should pay attention to the following aspects: first, choose the most scientific and reasonable anticorrosion construction materials, such as radiation crosslinked polyethylene heat shrinkable tape and epoxy resin anticorrosion materials, which are widely used at present; Secondly, in the process of anticorrosion, the joint position should be treated to some extent. Generally, the joint of the pipeline is derusted by sandblasting, and then the joint is preheated by a flame heater. After the preheating temperature reaches the relevant standards, the next operation can be carried out. Only by strictly following the prescribed procedures can the anti-corrosion effect of the pipeline be better guaranteed.

5 concluding remarks

In a word, the natural gas pipeline project, as an urban infrastructure project, is related to the daily life and safety of residents. Relevant enterprises and construction personnel must carry out construction in strict accordance with relevant construction procedures and rules and regulations to ensure the construction quality of gas pipelines.

References:

Ji Cheng. On the construction quality control of natural gas pipeline engineering [J]. Modern industrial economy and informatization, 2015 (16): 87-88+109.

[2] Jiang Kun. On the construction quality control of urban natural gas pipeline project at present [J]. Research on modern state-owned enterprises, 2015 (24):121.

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