Standard practice for these key procedures for tunnel construction, don’t tell me you still don’t know

Standard practice for these key procedures for tunnel construction, don’t tell me you still don’t know

Tunnel excavation, hollow bolt grouting quick joint, shotcrete, steel arch overall processing, connecting plate processing and installation, second lining steel installation, waterproof treatment, two-line concrete, lining concrete health, cable trench and drainage ditch, etc.What should be done with standard practices such as the construction of these tunnels?

What should I pay attention to during on-site construction?

I used to go to the standard construction site to observe and find the answer I wanted.

The three-step and seven-step excavation method used for excavation of the tunnel excavation tunnel is mainly to divide the tunnel into seven excavation faces while excavating at the same time, and at the same time support, form a whole support, and gradually advance to the depth.The method has the advantages of large construction space, high degree of mechanization, simple initial support process, flexible adjustment, high work efficiency, stable schedule and strong guarantee period.

Three-step and seven-step excavation tunnel smooth blasting appearance Three-arm rock drilling rig construction operation Tunnel three-arm rock drilling rig “two-machine single-hole” mode for tunnel excavation, effectively improving rock drillingSpeed, safety factor and environmental protection have improved the tunnel construction environment.

Hollow anchor grouting quick joint grouting quick joint has the following advantages: (1) quick and quick installation; (2) joint with anchor bolt and grouting pipe, which can effectively ensure grouting pressure and full grouting;3) The quick joint valve can be reused, which reduces the construction cost; (4) Improves the construction conditions of the previous artificial hand holding pipe grouting, and solves the problem that the worker’s eyes are easily splashed by the slurry during the grouting process.

Hollow anchor grouting quick joint grouting operation, safe and rapid sprayed concrete using wet spray machine construction tunnel initial support concrete, initial shotcrete compact and smooth, stable quality, effectively solve the dust in the traditional construction process, reboundHigh and unstable concrete quality issues.

The use of wet spray machine to construct the tunnel initial support concrete greatly improved the construction environment of the tunnel shotcrete, ensured the safety and health of the operators, and required fewer operators and less material loss, in line with the energy-saving and environmentally-friendly construction concept.

The tunnel adopts the secondary spraying process to construct the initial support concrete, and the secondary re-spraying of the initial spray unevenness part ensures the flatness of the sprayed concrete surface, and eliminates the quality hazard of the void behind the second liner due to the uneven surface of the sprayed concrete.

Using wet spray machine for initial shotcrete construction initial shotcrete surface smoothing solid steel arch frame overall processing steel arch processing: 1 according to the total length of tunnel steel arch frame once in place, and overall cold forming.

2 The section size is cut according to the section size set by the tunnel excavation plan.

The process can ensure the correctness of the size of the steel arch from the source, so that the overall arc shape is smooth after the arch frame is formed, the axes of the adjacent segments at the joint are coincident, the position of the connecting hole is accurate, and the structural force performance of the arch frame is ensured.
The overall cold forming of the steel arch frame is based on the scheme. The formed arch frame segmented steel arch frame segment finished product connecting plate processing and installation steel arch connecting plate and I-beam are welded by carbon dioxide welding, and the weld quality is good.

The carbon dioxide protective flux has the advantages of strong penetrating power, large penetration depth, good weld formation, firm welding, strong crack resistance, reduced deformation after welding, and replacement of operation.

Connection plate processing machine tool connecting plate finished product: accurate size, bolt hole hole standard carbon dioxide protection welding machine welding work seam full, good welding quality second lining steel installation two lining steel bar positioning is the weak interval of tunnel quality control, to improve the second liningFor the installation quality of steel bars, the following installation process can be adopted to ensure the spacing of the steel bars, the spacing of the rows and the thickness of the protective layer to meet the design requirements.

1. According to the design requirements, accurately process the steel bars of various specifications, accurately control the position of the pre-reinforcing steel bars on the side wall of the arch, and grasp the source of the accurate positioning of the second lining steel bars.

2, set up the installation trolley and positioning frame for the positioning of the steel bar, make full use of the standard interlayer connection structure to accurately control the spacing of the two-layer two-layer steel bar to ensure the accuracy of the hoop position of the steel bar.

3, using the fixture positioning, control the initial spacing of the main ribs; adjust the steel skeleton line shape by pulling the wire.

4, the use of high-strength concrete blocks as a two-line steel reinforcement layer strengthening measures to ensure that the thickness of the steel protective layer is strict.

Use the card slot to locate the vertical spacing of the main ribs, and weld the horizontal structure steel bars. Use the standard size of the interlayer connection structure to accurately control the spacing of the two lining two layers of steel bars to adjust the position of the steel bars to ensure the smooth mesh surface is used by special trolleys and positioning frames.The second lining steel bar is installed with two lining steel bars in an accurate position. The lining and the lining trolley template are closely attached. The thickness of the protective layer is qualified and installed. The second lining steel frame is stable and tidy. The linear round and smooth waterproof treatment is fixed by the hot melt positioning device.The hot melt pad of the plate can be fixed at the initial branch of the tunnel by the nail, and the waterproof plate is welded to the hot melt pad through the electric heat fusion joint, so that the waterproof plate is closely attached to the initial branch or the surrounding rock, and the elastic is moderately tight., effectively reduce the second liner void.

The structure of the two-lined trolley end template is improved, and a middle-mounted waterstop insertion slot is arranged in the middle of the end template according to the design position, the end template is installed at the same time as the waterstop, and the waterstop is fastened by special bolts on the template.The position is guaranteed to be accurate and sturdy.

The overall effect of the hot melt pad is the overall effect. After installation, the end template is pre-buried and the water stop belt is positioned accurately. There is no loose and damaged disease. The second lining concrete controls the quality of the raw materials, adjusts the concrete slump in real time, improves the vibrating process, and strengthensThe maintenance and maintenance of the formwork trolley makes the surface of the second lining concrete flat, compact, smooth and uniform in color, and achieves the effect of internal and external beauty.

The second lining concrete joint is smooth, the color is consistent, the second lining concrete surface has no pores, the sand line appearance defect, the second lining concrete surface, the smooth and smooth lining, the concrete, the second lining concrete sprinkling, the health sprayed concrete, the sprinkling, the health cable trench and the drainage ditch, the large steel mold is used for on-site pouring.The tunnel cable trench and drainage channel better control the cable trench and drainage line shape, the concrete surface is flat and compact; the cable trench and the drainage ditch are plastic shaped molds, vibrating table vibrating construction, good area, stable dimensional standard, convenientinstallation.

Cable trenches and drains after drain installation cover cable trenches