With the continuous development of China’s highway construction industry, highway tunnels have become an important part of highway engineering construction. Highway tunnel is a relatively special structure and a large project in highway construction. In the construction of highway tunnels, appropriate construction technology must be used to effectively improve the level of construction management so that the construction of highway tunnels can be carried out smoothly and the quality of highway tunnel construction can be effectively guaranteed.
Analysis of Construction Characteristics of Highway Tunnels
1.Strong concealment during construction
Hiddenness is the main feature of highway tunnel construction. During the construction of a highway tunnel, only external works are visible, and other works are hidden. As for the evaluation of highway tunnel construction quality, it is necessary to complete not only the assessment of the surface of the highway tunnel, but also the inspection of the deep conditions of the tunnel. At the same time, the geological environment needs to be strictly surveyed during the construction of the highway tunnel, because the geological conditions are likely to change, the construction design must pay great attention to the changes in the geological conditions to ensure that the construction design is dynamic.
2.Poor construction environment
For highway tunnel construction, tunnel excavation, ventilation and support operations must be completed in the same construction environment. Because the working surface is relatively small, and the construction process is very compact, there are a lot of construction technicians and construction facilities to be deployed, so the construction space is small and the construction work is crowded. In addition, the internal environment of highway tunnels is extremely harsh, with relatively low visibility, poor air circulation, and high noise, which will also have a certain degree of negative impact on the physical and mental health of construction technicians.
3.Strong professionalism in construction
The construction period of highway tunnel engineering is relatively long, and the length of the project is also very long. During construction, the phenomenon of cutting corners and cutting materials often occurs, which seriously affects the quality of highway tunnel construction and it is difficult to meet the requirements of highway engineering quality standards. In this case, the highway tunnel engineering supervision staff must have solid professional knowledge and skills, conduct strict inspections and supervision of highway tunnel construction, and timely discover and resolve construction quality problems. At the same time, highway tunnel construction has strict requirements on professionalism, so construction technicians and construction facilities must meet the requirements of the standard.
Key points of highway tunnel construction technology
1.Technical points of tunnel opening construction
In the process of designing the construction technology of the opening of the highway tunnel project, it should be unified with the construction of adjacent projects. Not only must the construction quality of the tunnel tunnel be effectively guaranteed, but the construction efficiency must also be effectively improved.
At the same time, the construction of highway tunnel openings needs to avoid the rainy season and low temperature periods, so that the construction quality of highway tunnel openings can meet the requirements of standards. Before the construction of highway tunnel openings, it is necessary to remove overhanging and dangerous rocks in time to enhance the reliability and stability of the hillside, so as to create a safe construction environment for construction technicians. It is also important to monitor and protect the tunnel opening during construction, because road tunnels may change during construction. Therefore, according to the construction site conditions, the slope of the tunnel opening and the slope of the tunnel must be protected to ensure the tunnel opening In a safe and stable state. In addition, the construction period of the highway tunnel project is relatively long. In order to facilitate the successful completion of the project, drainage facilities should be effectively established before the rainy season to promote the completion of the tunnel tunnel opening within the prescribed period.
2.Key points of construction technology of tunnels and open doors
For the construction of open tunnels for highway tunnels, construction technicians should construct according to the construction plan and design requirements. First of all, pre-reinforcement of the ground floor should be carried out before the construction of a highway tunnel open hole, and the construction technology method of layered excavation should be selected. In order to ensure the normal construction of open tunnels in highway tunnels, the construction technicians must also complete the support treatment, especially the slope and Yang slope support generally use a combination of multiple support methods to further strengthen the side Slope, slope stability. Secondly, the construction of the highway tunnel’s open hole is started. For the construction of the side wall of the tunnel, the foundation reinforcement needs to be completed before construction. At the same time, the width and buried depth of the side wall of the highway tunnel’s open hole must meet the requirements, so that the highway The construction of the tunnel open hole is consistent with the design plan.
The key points of the construction technology of the highway tunnel door must pay great attention to the following points:
A. In the construction of highway tunnel doors, the construction efficiency should be improved as much as possible, the construction period should be shortened, and the construction should be completed before the rainy season comes.
B. The construction of the tunnel door wall of the highway tunnel must be carried out in a timely manner after the excavation of Shishi, and it is also necessary to ensure that the bearing capacity of the tunnel door port wall and the wing wall base meet the specific requirements specified in the design plan. If the problem of uneven soft and hard foundations occurs during the construction of the wing wall of the tunnel door or the port wall, it will inevitably have a serious impact on the highway tunnel project. Therefore, the construction quality of the highway tunnel door must be strictly controlled.
C. Tunnel excavation is an important part of highway tunnel construction, and all preparations must be completed properly before tunnel excavation. In order to improve the bearing capacity of the surrounding rock of the highway tunnel, the corresponding protective measures should be used for reinforcement treatment, and the tunnel excavation can only be carried out on the premise of ensuring its stability. At present, the technologies commonly used in highway tunnel excavation construction are blasting construction technology, pre-splitting construction technology and non-blasting machinery-assisted construction technology.
From the analysis of the application of highway tunnel excavation construction technology, the specific construction process is as follows: firstly, the arch is excavated, mainly using smooth blasting technology; secondly, the side wall is excavated, and generally the pre-split blasting construction technology is selected; Finally, excavation of the floor should be reserved, so that it can create favorable conditions for the effective application of smooth blasting construction technology. In addition, before the highway tunnel is excavated, strict and effective tests on the relevant technical parameters need to be completed, so that the highway tunnel excavation can be carried out smoothly.