What are the tunnel construction process?

Tunnel construction is a common underground excavation construction method. The quality of tunnel construction generally depends on the quality of the workmanship. That is to say, the quality of excavation, initial support, and waterproof and drainage must be mastered in the process of tunnel construction. Only after the quality of these processes can we guarantee the quality of tunnel construction. In addition to mastering the quality of tunnel construction, we also need to understand the construction process. What about the tunnel construction process and technological process?

1. Advance support construction of large pipe shed and small pipe shed

The main content of the construction of the large pipe shed: construction of the guiding wall embedded guiding pipe, setting of the drilling platform, measuring the hole position, drilling, drilling rig exit, injecting grouting, and sealing.

The tunnel concrete maintenance formwork

2. System bolt construction

The hollow grouting anchor rod used in the tunnel construction system anchor rod, the anchor rod is 4m (radial) or 5m (inner level), the circumferential spacing is 1m, the pneumatic drill is used for drilling, and the diameter of the hole is Φ40mm. After the hole is formed, the hole is cleared by high-pressure air, manually fed, and sealed with quick-setting mortar. The grouting pressure is guaranteed to be 0.5~1.0mpa, the diffusion radius is the largest, the effect on the surrounding rock is the best, and the poor geology with more developed fractures. The graded surrounding rock has a good improvement effect, the pull-out resistance meets the design requirements, and the end of the anchor rod is welded to the arch frame.

3. Construction of rigid arch support

The large sample is released in the processing site and processed in sections by a bending machine. The quality of installation control (center line, elevation, verticality) is mainly used, and the offset and suspension methods are mainly used in the construction. Also pay attention to control the processing size and connect each mesh into a whole.

The tunnel concrete maintenance formwork

4. Construction of temporary support (temporary side wall support, temporary invert)

Due to poor geological conditions, the convergence value of the side wall of the temporary inverted arch has exceeded the limit through data analysis. According to the actual situation, analyze, research and test to ensure safety. I22mm is installed between the main and adjacent arches during the excavation and support of the upper section pilot pit. The horizontal support and support, which solves the problem of excavation safety and the excessive deformation of the subsequent leg and upper arch during the stress redistribution process, the stress release is out of control, which causes the arch fall, block, crack and collapse.

5. Second lining concrete construction

The secondary lining is a part of the permanent bearing structure of the tunnel project, which plays an important role in improving the service life and appearance quality of the tunnel. The lining is divided into two parts, one is the secondary lining of the arch, and the other is the invert of the lower tunnel bottom. Lining.

Tunnel formwork channel

6. Construction of the water system inside and outside the cave (prevention and drainage)

The quality of the water-proof and drainage system in the cave must be strictly controlled. It must follow the inside and outside of the cave; the combination of permanent and temporary water-proof and drainage, especially the installation of the drainage half pipe and the position, depth, and angle of the drainage hole, are usually controlled by us. A negligent process. After years of construction experience, the groundwater treatment of the tunnel is one of the important processes related to the safety of future operations.

The tunnel construction process and technological process are the above points. During the tunnel construction process, we must master the construction process and technological process, which must be mastered during the tunnel construction process, otherwise the construction cannot be carried out.