Safe for 5 minutes daily
Issue 005 (104 issues in total)
Zhang Gong said safe, five minutes a day.
Alarm bells ring all the time, and there is no moment of relaxation.
5. Tunnel construction - lining safety control points
First, lining steel bars
1. No steel reinforcement shall be processed in the tunnel. The installation of lining reinforcement should be equipped with temporary supports, which are reliable and have eye-catching safety warning signs.
Generally, the processing of the centralized reinforcement processing plant is transported to the construction site of the second-lined steel bar of the tunnel, and the simple bench of the waterproof plate is used as the steel bar lashing construction platform for steel bar construction.
2. Flame retardant baffles should be set up for steel welding operations (flaps should be set up for fire operations) to prevent fires and poisoning accidents caused by ignition of waterproof plates.
Second, the tunnel safety step requirements
According to the provisions of The Railway Construction [2008] No. 160 Document: the distance between the arch and the palm surface is required: the distance between the 1, I., II., III. surrounding rock section should not be greater than 90m from the palm surface; the upward arch distance of the grade IV surrounding rock section should not be greater than 50m from the palm surface; the upward arch distance of the V., VI. surrounding rock section should not be greater than 40m from the palm surface. The distance between the secondary lining and the palm surface is required: the second lining distance of the grade I. and II surrounding rock section should not be greater than 200m from the palm surface; the second lining distance of the grade III surrounding rock section should not be greater than 120m; the second lining distance of the iv. and above surrounding rock section should not be greater than 90m or the design regulations.
According to Jianji [2010] No. 352 and Iron Construction [2010] No. 120, the enclosed position of grade IV., V., VI. surrounding rock shall not be greater than 35m from the palm surface. Secondary lining Class IV surrounding rock shall not be greater than 90m, and Grade V and VI surrounding rock shall not be greater than 70m. In summary, the following provisions should be adopted for the current construction of railway tunnels:
The distance between the arch and the palm face is required:
The upward arch of the I., II., III. surrounding rock section is ≤ 90m from the palm surface; the upward arch of the Class IV surrounding rock section is ≤ 50m from the palm surface; and the upward arch of the V., VI. surrounding rock section is ≤ 40m from the palm surface.
The distance between the secondary lining and the palm face requires:
The second lining of the Grade I., II. surrounding rock section is 200m from the palm surface≤, the second lining of the Class III surrounding rock section is 120m from the palm surface≤, the second lining of the Class IV surrounding rock section is 90m from the palm surface≤, and the second lining of the V. and VI. surrounding rock section is ≤ 70m from the palm surface.
The safety technical specifications for highway engineering construction (JTGF90-2015) stipulate that the tunnel lining of weak surrounding rock and bad geology should be implemented in time, and the distance between the secondary lining and the palm surface shall not be greater than 90m, and the distance between the secondary lining and the palm surface shall not be greater than 90m, and the V. surrounding rock shall not be greater than 70m.
Three, two-liner trolley
1. After the completion of the assembly of the ledger, it should be accepted and debugged (trial walking), and it can be put into use after it is qualified, and the trolley should be equipped with protective railings, warning signs, and fire fighting equipment. Daily use should be maintained according to the prescribed requirements.
2. After the lining trolley and the steel and waterproof plate work trolley are in place, an anti-slip device should be set up, and the hydraulic support should have a locking device.
3. During the construction process, the support system should be checked to prevent mold explosion and deformation of the trolley.
4. The trolley cable should be passed into the PVC tube.
Fourth, waterproof board construction
1. The waterproof board operation area should be set up with fire fighting equipment and fire safety warning signs.
2. The lighting fixtures on the working surface of the waterproof board shall not bake the waterproof board, and the distance from the waterproof board shall not be less than 50cm, and there is no fire hazard on the working surface of the waterproof board.
Fifth, concrete pouring
1. The speed of the vehicle shall not exceed 5km/h during the construction of the arch, and there shall be a special person to direct it.
2. When pouring arches and filling concrete, the construction workers under the trestle should avoid passing vehicles in advance.
3. The arch concrete should be poured at one time, and the left and right half of the piece should not be poured in batches, and the length of the one-time pouring should not be more than 5 meters. Mainly to control the exposure distance of the arch excavation.
【Zhang Gong said safety】
Tunnel safety management and housing safety management have a big difference, tunnel safety is mainly program security, or technical safety, many technical measures are to ensure that the tunnel itself is safe and controllable, as long as the program is in place, most of them can ensure safety and controllability. Many hidden dangers are that the implementation of eventful technical measures is not in place. Therefore, if the pipe tunnel does not look at the technical solution and does not understand the technology, then the safety management personnel will have nothing to do when they go to the scene, or only take care of the fur, which must be recognized, otherwise no matter how many people are arranged, it will not help.
Tunnel in the past construction has the first pouring of low side wall situation, in the cable trench top surface to add a longitudinal construction joint, because the lining side wall foot contour line is mostly curved, easy to appear irregular forming, insufficient thickness and other issues, there are hidden dangers, so in the highway construction specifications clearly "shall not first pour low side wall".
Check the workload tunnel construction specifications, requiring arch wall lining and back arch lining to form a whole, which can effectively transmit axial forces and bending moments. However, due to the limitations of the site and construction process, in reality the back arch and arch wall lining is distributed to complete, forming a working seam, and all construction specifications stipulate:
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