Overview of the safety technical measures for rail descent and thin spraying in the mining area?

In view of the fact that the track downhill and the stone gate of the -22 mining area are cross-layer tunnels, the local lithology is poor. In addition, this roadway is a roadway prepared for the mining area and has a long service life. In order to prevent the lithology of the roadway from weathering over time and ensure its service life, according to the production plan, it was decided to carry out thin spraying technology construction on the track downhill and the stone gate in the -22 mining area. In order to ensure construction safety, these construction safety technical measures are specially formulated.

1. Overview:

1. Construction location: -22 Mining Area Track downhill, a stone gate.

2. Construction content: thin spray sealing of the top and surrounding rocks of the tunnel.

3. Construction site safety assessment:

2. Labor organization:

Project leader: Position: Captain

Safety person in charge ：Yu Jinfa and follow-up team members

Construction leader: each shift monitor

Construction personnel: each shift operator, etc.

Safety inspector: each shift follow-up Team leaders and installers?

3. Construction time: from the date the measures are issued until the end of the thin spray construction.

IV. Preparation before grouting:

1. Prepare equipment and tools for grouting such as slurry mixer, grouting pump, high-pressure hose, nozzle, etc., and install them at on-site work locations.

2. Prepare composite materials, cement, and strengthening materials for shotcrete.

3. Prepare spraying materials as required: the proportioning method is: 100kg of water (two boxes), 200kg of cement (4 bags), 15kg of strong materials (half a barrel), 17.5kg of composite materials (half a bag). It is required to stir the spray material evenly.

5. Construction methods and techniques

1. Personnel composition:

Loading: 2 people, mixing: 1 person (mixing driver), electric fitter on duty : 1 person (concurrently), spray hand: 1 person, pump driver: 1 person, squad leader: 1 person (concurrently).

2. Cleaning up of the working site before grouting:

(1) Remove obstacles in the working area and clear away floating waste and debris on both sides of the excavation working face.

(2) Embed signs to control the thickness of sprayed cement-based slurry.

(3) When the pump driver and the sprayer cannot communicate directly, a communication device should be equipped.

(4) Good ventilation must be ensured in the working area.

(5) Before spraying, flush the top of the tunnel with water.

3. Check the equipment:

(1) Before the grouting pump is operated, check the grouting pump and supporting equipment. Ensure the normal operation of construction machinery and tools.

(2) Check the air ducts and shotcrete pipes to ensure that each pipe is smooth and does not leak air or liquid.

(3) Protect the cables and pipelines of the tunnel being sprayed. Put down the cables and block them. Wrap or block the cables, cable hooks, pipelines, etc. with plastic sheets.

(4) Transport the materials required for spraying to the spraying location, and adjust the spraying equipment to ensure the normal operation of the equipment.

4. Shotcrete construction technology:

(1) Add water into the mixing barrel according to the preparation ratio requirements, and start the mixer. Add strong materials, cement and composite materials according to the proportion of preparation.

(2) Close the ball valve on the mixing barrel and let the mixing enter low-speed mixing. Open the screw pump ball valve, and the screw pump motor drives the screw pump to rotate and transport the slurry out.

(3) Start the equipment to spray grout, first spray it from one direction, and then spray it again from the other direction after it is basically solidified. The top can be sprayed twice as needed to clear the cracks in the coal wall and Spray evenly around the anchor net. When spraying grout, stick to the top first and then the top, and proceed from top to bottom.

(4) After grouting, promptly clean up debris on site and flush the mixing barrel, grouting pump and pipelines.

(5)-22 The order of spraying the track down the mountain in the mining area is: from top to bottom. After the spraying is completed, spray again from bottom to top. The spraying method of Shimen is the same as that for the track down the mountain. Ensure the tunnel is sprayed evenly.

5. Requirements for mixing the mixture:

(1) The allowable deviation of the weighing of raw materials is ±1 for various materials.

(2) The proportion of the mixture is: 100kg of water (two boxes), 200kg of cement (4 bags), 15kg of reinforcing materials (half a barrel), and 17.5kg of composite materials (half a bag).

(3) Add water first, then reinforce the strong materials, add cement, and then add composite materials.

(4) When loading cement, add bags one by one and stir. After one bag is evenly mixed, add the next bag until the loading is completed.

(5) When stirring, generally rotate forward for one minute, reverse for one minute, repeat 3 times, and stir for about 6 minutes. Stir until it becomes a paste and you can start spraying.

6. Operation of the nozzle:

(1) Spray angle of the nozzle: When the nozzle is seriously deviated from the vertical direction, the sprayed cement-based slurry will roll or continuously spray on the sprayed surface. Overlap, the spray angle of the nozzle should be kept perpendicular to the sprayed surface as much as possible.

(2) The distance between the nozzle and the spray surface: The distance between the nozzle and the spray surface is appropriate so that the slurry rebounds less and the pouring force is strong. This distance is 1.5-2 meters more suitable.

6. Safety technical measures:

(1) General safety technical measures:

1. All personnel must hold certificates and strictly implement various regulations. The system strictly prohibits illegal operations and illegal command.

2. Strictly implement the "finger dictation" safety confirmation system. Each type of work and each process will be subject to safety inspections before operation. If there are no problems, "finger dictation" safety confirmation will be carried out.

(2) Roof management:

Strictly implement the system of asking for help. The squad leader assigns experienced employees to use long tools (≮2m) to inspect the construction site and the tunnels along the way. Carry out knocking and roofing operations to remove hanging rock and provide support in a timely manner. This work must be carried out by two people. The retreat route must be cleared in advance, one person shall supervise, and the other shall ask questions, step by step from the outside to the inside. And deal with the top plate first and then the two gangs.

(3) Safety technical measures for shotcrete:

1. All preparations and safety inspections must be done before shotcrete. When mixing materials, an appropriate location must be selected so as not to affect other operations such as transportation.

2. Before spraying, clean the floating gangue on both feet of the tunnel and clear it to a solid bottom to ensure that there are no slipping or wearing skirts after spraying.

3. Check the operation of the grouting pump before grouting, including the fastening of each component. Make sure the seal is intact and the lubrication is normal. When problems are found, they must be dealt with before starting the operation.

4. After spraying, the pipes and cement in the pump must be cleaned with clean water.

5. Shotcrete work is generally carried out by two people, and they must cooperate closely to handle problems in a timely manner. The sprayer must master the spray angle and distance, and strive to spray vertically on the rock surface. It is strictly forbidden to point the gun head at people under any circumstances.

6. Before spraying, use old air ducts, plastic sheets or other materials to protect electrical equipment, cables, feng shui pipes and other facilities within the spraying range; carefully clean up the cables after spraying. , mechanical equipment and floor-mounted rebound materials to clean and smooth the ditch. The cleaned rebound material must not be loaded into the vehicle immediately. It must wait for solidification before loading to prevent the rebound material from solidifying in the vehicle.

7. Before spraying, the construction team must remove all dangerous rocks on the roof of the tunnel. In areas where metal mesh is used, the corroded metal mesh must be knocked to remove the rust before spraying, and at the same time, there are many rocks in the mesh to be released. If the anchor mesh has fallen seriously, anchor rods must be added first to make the mesh close to the rock. surface, and then wash away the dust in the tunnel. For the sections where the top rock is more broken, the amount of water should be reduced and sprayed several times to achieve the purpose of sealing the cracks.

8. The sequence of grouting is: add water → open the mixing bucket → load materials for preparation → start the grouting pump → spray. When shutting down: stop material → stop water → stop air.

9. When dealing with a blocked pipe, a special person should be sent to hold the spray gun head firmly. No pressure is allowed to be used. Stop the air, open the liquid return valve and knock the blocked pipe, and then close the liquid return valve to supply air for treatment.

10. When the percussion method is used to solve the problem, the pipeline must be disassembled after stopping the air flow.

11. When removing debris from the mixing barrel or grouting pump, the air must be stopped first, and a special tool clip or long-handled tool should be used to remove the debris from the body. It is strictly prohibited to reach out and take it directly.

12. The gun head is not allowed to point at people under any circumstances. 13. Before spraying, the ventilation team shall set up two sets of dust-proof water curtains in the return air flow according to regulations, and they are required to be in a normally open state during spraying.

14. Before spraying on the slope, the construction team will complete the slope lifting signal, and then set up another signal to remotely control the winch lifting with the operation of the spraying machine. After all personnel under the shotcrete machine before lifting have entered the safety cave to take cover, the signal worker can only send the lifting signal in the shelter cave.

15. Special personnel must be designated to operate the power supply in inclined lanes or flat lanes. When dealing with shotcrete machine failure or feed blockage, the power and wind must be cut off first, and the switch must be locked. After the maintenance personnel have completed the processing and contacted each other, power supply, power outage, air supply, and wind stop can be started. When the shotcrete in the inclined lane is completed, the shotcrete machine must first cut off the power and wind, and then lift the shotcrete machine into the level lane of the loading and unloading yard. The shotcrete machine is not allowed to be lifted or lowered while powered.

16. Before spraying on inclined tunnels, the construction team must conduct a comprehensive inspection of the stability and integrity of mechanical equipment (winches, steel ropes, pressure columns, ground anchor piles), air ducts, shotcrete pipes, water pipes, etc. And test operation, if any problems are found, the power or wind must be cut off first and then dealt with.

17. When spraying, feed water first and then feed materials. It is strictly forbidden to stand in front of, on the left and right sides of the spray gun, or under the mine car and the spray machine.

18. The number of trains to be lifted by the winch in the inclined tunnel is: one shotcrete machine and one mine car. It is strictly prohibited to over-pull and over-hook, it is strictly prohibited to push the hook, and it is strictly prohibited to operate by unlicensed personnel. The diameter of the winch steel rope is not less than 18.5mm. The shotcrete machine and the mine car must be fixed after they are lifted into place and stopped. The fixing method is to use a 12.5mm diameter steel rope to pass under the downhill track of the shotcrete machine and the mine car respectively, and then use three rope clamps to fix it on the track to prevent the shotcrete machine and the mine car from sliding down.

19. The order of spraying is first the top and then the top. When spraying the wall, start from the top of the vault and go from top to bottom. Work backwards. The up and down speed of the shotgun should be uniform, and the proportion should be controlled on-site. When loading the shotcrete, it must be uniform and timely to prevent it from being inconsistent.

20. There are two people to operate the spray gun, and one person holds the spray gun. When spraying, the personnel should hold the spray gun and straighten their arms to spray diagonally (that is, the spraying point and the person should be no less than 1.5 meters distance) to prevent bumping, help falling debris and hurting others. Another person moves the feeding pipe, and pays attention to the rubber hose not to make any dead bends, which may cause blockage.

21. The spraying thickness is 10mm. If the spraying is not sufficient at one time and additional spraying is required, the interval is 15 to 20 minutes. After the spraying reaches solidification, spraying is performed a second time.

22. When the spraying is completed, stop feeding the material first and continue to pour water into the mixing barrel. Wait until the material inside is sprayed and the material discharged from the gun head becomes clean water, then stop pouring water and remove the excess water in the barrel. After spraying all the clean water, stop the wind, remove the gun head, and pack away the work tools.

23. If there are people passing by during the spraying process, they must contact each other before passing.

24. After the spraying is completed, the construction unit will collect the remaining mortar in the working section. When the mortar is not solidified, it will be used as a ditch to ensure civilized production and ensure that the cables are hung flat and straight. on the cable hook.

25. During the upgrading process, the principle of "vehicles but not pedestrians and pedestrians not driving" must be strictly implemented.

26. During the construction of thin spray technology, the Production Department and the Machinery Department sent people to the site for technical guidance.

27. Others shall be carried out in accordance with the "Operation Procedures" and relevant regulations.

Attachment: Job Responsibility System

1. Project leader:

1. Fully responsible for the construction method and construction sequence.

2. Pay attention to the construction steps and safety precautions during thin spraying.

3. Responsible for the organization, coordination and on-site safety inspection during the construction period. Construction will not start until safety requirements are met.

4. Follow the construction site during the construction process, check the safety problems encountered during the construction process and deal with them in time to ensure the safety of on-site construction. After construction is completed, be responsible for quality acceptance.

2. Safety person in charge:

1. Carefully check the roof of the construction site before construction and be responsible for personal safety during construction and safety during construction.

2. Tools, equipment, and materials must be prepared before project construction, and the operation can only be allowed if conditions are met.

3. Possible hidden dangers in every link and every step must be pre-controlled in advance, and construction measures must be strictly followed on site.

1. After the construction is completed, conduct a comprehensive inspection of the working surface and construction conditions to ensure that there are no safety hazards.

3. Construction person in charge:

1. Responsible for the organization, arrangement and coordination of personnel during the construction period.

2. During the construction process, be responsible for coordinating with relevant units to ensure the supply of materials is in place and make preliminary preparations for production work.

3. Reasonable division of labor and direct specific work construction according to measures.

4. Safety supervisor:

1. Supervise the implementation of safety technical measures on site;

2. Supervise the implementation of the three major regulations on site ;

3. Have the right to stop illegal operations and illegal command behaviors

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