Urban underground integrated pipe corridor construction technology
2023-01-05 15:15:55

In the context of continuous development of social and economic construction, the pace of urbanization in China is also advancing. With the improvement of urban infrastructure, the utilization of urban underground space has become more and more frequent. In order to effectively improve the utilization of urban underground space and avoid conflicts between various engineering pipelines, it is necessary to construct urban underground integrated pipeline corridor. This paper will start from the advantages, classification and shortcomings of the urban underground integrated pipe corridor project, and elaborate its construction technology.
First, the urban underground integrated pipe corridor project overview
 
 1.1 Analysis of the advantages and disadvantages of urban underground integrated pipeline corridor project
       At present, the development of urban underground integrated pipe corridor project has a history of more than 100 years, and a perfect system has been basically formed in the long-term development process. It can be concentrated in the corridor to arrange a variety of urban infrastructure pipelines, reduce the occupation of cables, poles and other infrastructure in the city near the ground space, on the other hand, to avoid repeated excavation to bring inconvenience to urban road traffic. Outside, urban underground integrated pipeline corridor can provide good protection for various infrastructure pipelines, especially for some disasters and accidents. As the distribution of various pipelines is relatively concentrated and underground, it can effectively avoid the damage that may be caused to the pipelines due to the breaking and tipping of poles. Damage caused by urban residents.
Although the urban underground integrated pipeline corridor project has the above advantages, its disadvantages are also ignored, mainly in the following points: First, the underground integrated pipeline corridor project includes large concrete structures, which requires a lot of financial support. Secondly, the underground integrated pipe corridor has high requirements in terms of waterproof and moisture-proof.
1.2 Analysis of urban underground integrated pipeline corridor types
According to different criteria, different classifications can be made for urban underground integrated pipeline corridors. For example, according to the classification standard of function, the underground integrated pipeline corridor can be divided into trunk integrated pipeline corridor, branch integrated pipeline corridor, dry and branch integrated pipeline corridor, cable integrated pipeline corridor and so on. According to the classification according to the construction method, the underground integrated pipeline corridor can be divided into open excavation underground integrated pipeline corridor and underground excavation underground integrated pipeline corridor. It should be noted that with the former construction method, the influence of the external ground environment needs to be fully considered in the construction process.
1.3 Empirical analysis of urban underground integrated pipeline corridor construction
The construction of urban underground integrated pipeline corridor can provide guarantee for the comprehensive and coordinated development of urban space. It can realize the rational application of urban underground space, promote the improvement of urban infrastructure, reduce unplanned infrastructure construction, keep the city healthy and well improved the development trend of urban underground space, and reduce the adverse impact of pipeline maintenance on urban road traffic and residents' life. In addition, the construction of urban underground integrated pipeline corridor also improves the city's disaster prevention and resilience.
1.4 At this stage, China's urban underground comprehensive pipeline corridor construction faces common problems
Combined with the construction practice of China's urban underground integrated pipeline corridor project in recent years, the more common problems are concentrated in the following areas.
First, there are risks in system planning and design. Because the construction of urban underground integrated pipeline corridor project is a one-time, so it is necessary to predict the future development of the city before the construction of the project scientific planning, comprehensive consideration of the future development of the city, complete the planning and design of the urban underground integrated pipeline corridor project. On the one hand, the waste phenomenon should be strictly controlled, on the other hand, to ensure that it meets the needs of urban development, so as to ensure that the role of the integrated pipe corridor is fully utilized. But no matter how accurate the forecast, it is impossible to be completely accurate, which brings a certain risk to the planning and design of the integrated pipe corridor.
Second, the financial pressure. Since urban underground integrated pipe corridor projects need to be built at once, large-scale capital investment is required at the early stage of project construction, and such infrastructure usually needs to rely on government finance or related financing policies, so problems often arise due to financial constraints.
Finally, the legal and standard system related to the construction of urban underground integrated pipe corridor in China is not yet perfect. At present, China's relevant laws and regulations have not yet made clear provisions on the operation, property rights and costs of urban underground integrated pipeline corridors, resulting in many problems arising in the construction and operation of integrated pipeline corridors are not effectively resolved. On the other hand, due to the imperfect construction standards of urban underground integrated pipeline corridor, the lack of necessary specifications for specific construction has caused quality problems
1.5 The specific process of urban underground integrated pipeline corridor project construction
In the construction process of urban underground integrated pipeline corridor project, it is necessary to strictly follow the standardized construction process and ensure the standardization of each process to ensure the safe and efficient implementation of construction activities. The construction of urban underground integrated pipeline corridor in order of priority is: I. Positioning measurement. According to the measurement and positioning coordinates and elevation control points provided by the construction unit, the integrated pipeline corridor is positioned and completed and controlled. Second, develop the plan. Prepare the project construction organization design and various construction plans. Third, earth excavation. Determine the size of the earth side slope according to the construction plan, and then excavate the earth layer by layer. Fourth, check the tank. After the foundation pit is excavated to the design elevation, the geological survey, construction, design and construction units will complete the inspection and acceptance together. Fifth, the construction of the whole floor and the main structure. The bedding layer and main structure of the underground integrated pipe corridor shall be constructed according to the design drawings. Sixth, the construction of waterproofing and moisturizing. Scientific connection construction with the main structure. Seventh, earth backfill. Combine the construction conditions and actual situation, choose suitable construction machinery for earth backfill, and pay attention to the structural design in the process. Eighth, secondary structure and plumbing and electrical installation. Combine with the main structure construction progress, organize the secondary structure and plumbing and electrical installation works. Finally, the acceptance of the project is in strict accordance with the standard specifications for each process acceptance.
Second, urban underground integrated pipe corridor construction technology discussion
2.1 Open excavation cast-in-place method
At the present stage of urban underground integrated pipe corridor project construction, the open-cut cast-in-place method is a very frequent method, which is characterized by the realization of large-area construction operations, and the entire project is divided into multiple construction sections to carry out simultaneous construction, which significantly improves the construction efficiency. At the same time, the open-cut cast-in-place method also has many advantages such as low technical requirements and low cost. The disadvantage is that the road traffic will be interrupted during the construction process, affecting the travel of urban residents. In the specific construction, the open-cut cast-in-place method is often used in the flat terrain and the surrounding relatively open lots, and the construction process is as follows: first, excavation and laying of pipes, according to the actual situation to choose the appropriate excavation method, while using well-point precipitation measures. Since there is no need to set up an enclosure around the perimeter during the construction process, it is very suitable for mechanized large-scale projects. The only point that needs special attention is that the excavation volume of the cut-and-cover method is larger, so the requirements for earth backfill construction are higher.
2.2 Shield method
The shield method is also more widely used in the construction of urban underground integrated pipeline corridor, which is more suitable for soft ground sections and can provide good protection. This method is more mechanized and therefore uses less human resources, reducing the difficulty of construction organization. The work of the construction personnel also favors the management of mechanical operations. Compared with other methods, the shield method is faster and safer, and can provide shield protection for many operations during construction. However, the shield method requires a high level of craftsmanship, and the construction unit using this method must have a strong overall capability. At present, the shield method is often used for the construction of urban underground integrated pipeline corridor projects in some more prosperous locations, such as areas with dense distribution of buildings, because it has little impact on the environment around the construction site. Although it has several advantages, the shield method also has certain defects, such as poor ability to adapt to engineering changes, high difficulty in controlling surface settlement when the tunnel cover is shallow, and high difficulty when performing small curve radius tunnel construction. In addition to these technical problems, the construction cost of shield method is high.
2.3 Shallow concealed excavation method
Shallow concealed excavation is a construction technique used to conceal all kinds of underground tunnels close to the surface, which is more suitable for locations with poor lithology, poor topography or the presence of groundwater. Compared with other construction methods, shallow concealed excavation method has the advantage of flexibility and can adapt to many terrains that are not suitable for shield method and cut-and-cast method. At the same time, it has less impact on roads and underground pipelines, so its application in urban construction is very common. When applying the shallow buried concealed excavation method for urban underground integrated pipe corridor construction, it is necessary to use a variety of auxiliary work methods, over-support, strengthen the stability and bearing capacity of the surrounding rock, and also do a good job of closing into a ring in time, so that it forms a joint support system with the nearby surrounding rock.
2.4 Construction methods of various types of sections
In the process of urban underground integrated pipe corridor construction, the construction unit should choose different construction technology methods according to different situations. For example, different construction techniques should be selected for various types of cross-sections. For example, for the circular section, the prefabricated assembly type slotted construction method or the construction method without slotting such as jacking construction and shield construction should be selected. For rectangular sections, prefabricated cast-in-place construction or shield construction should be selected. For heterogeneous cross-section, the shallow concealed method of jacking construction should be selected. It is necessary to pay special attention to the prefabricated assembly construction method is limited by the size of the section, the best to control the starting weight of 20 t or less.
2.5 Urban underground integrated pipe corridor main structure construction
First of all, before the construction of the main structure of the urban underground integrated pipe corridor, a perfect construction plan should be made, especially for the side wall, top plate, bottom plate and other parts of the pipe home, a reasonable disposal plan must be made. For the parts with deep burial, the thickness should be set reasonably. For the special node parts, it is necessary to take into account the empty space for all kinds of pipeline interpenetration