The following is the relevant content about the safety operating procedures for tunnel drilling and blasting excavation construction brought to you by Zhongda Consulting for your reference.
1. General provisions
1.1. The construction site should be arranged and settled in detail, the ballast discharge, feeding and material storage areas should be properly arranged, and the ballast disposal site should be set up in a different location. Areas that block rivers, do not pollute the environment, and do not destroy farmland. Make unified arrangements for wind, water, electricity and other facilities and basically complete them before entering the cave.
1.2. Before entering the tunnel, the tunnel entrance engineering should be completed first, the side slope and incline of the tunnel entrance should be stabilized, and drainage facilities such as gutters and side ditches should be made to ensure that surface water does not endanger the construction safety of the tunnel.
1.3. A complete handover system should be established between each team in tunnel construction, and construction, safety and other conditions should be recorded in the handover record book. The person in charge of the construction site duty should carefully check the handover situation. .
1.4. All personnel entering the tunnel construction site must wear safety protective equipment as required, abide by rules and disciplines, and obey instructions.
1.5. When constructing in areas with poor geology, we should proceed steadily in accordance with the principles of water control first, short excavation, weak blasting, strong support, and early lining. If adverse geological conditions are specified in the design documents, advance drilling should be carried out if necessary to ascertain the situation and take preventive measures.
1.6. These regulations apply to the construction of mountainous highway tunnels and do not apply to underwater highway tunnels.
2. Excavation, drilling and blasting
2.1 Excavation and drilling
2.1.1 When the excavator arrives at the work site, he should first check Check whether the working surface is in a safe condition, and check whether the support is firm and whether the roof and the two gangs are stable. If there are loose stones, soil blocks or cracks, they should be removed or supported first.
2.1.2 When manually excavating soil tunnels, operators must cooperate with each other and maintain the necessary safe operating distance.
2.1.3 When mechanical rock drilling, a wet rock drill or a rock drill with a dust collector should be used.
2.1.4 When working on a pile of ballast, attention should be paid to the stability of the pile to prevent slipping and collapsing and injuring people.
2.1.5 When drilling holes with a pneumatic drill, you should first check whether the body, bolts, ferrules, springs and brackets are normal and intact; whether the pipe joints are firm and whether there is air leakage; whether the drill pipe is not straight or damaged And whether the drilling hole is blocked; whether the water supply of the wet rock drill is normal; whether the dust collection facilities of the dry rock drill are good. Those that do not meet the requirements should be repaired or replaced.
2.1.6 When drilling holes with a pneumatic drill with a bracket, the bracket must be placed securely. When the pneumatic drill is stuck, use a wrench to loosen it and pull it out. Do not knock it. Do not remove the drill pipe before turning off the wind.
2.1.7 It is not allowed to disassemble or repair pneumatic or electric drills in the working surface.
2.1.8 It is strictly prohibited to continue drilling in the residual eye.
2.2 Blasting
2.2.1 Charging and drilling should not be carried out in parallel.
2.2.2 The blasting equipment processing room should be located in a safe place 50m away from the opening. It is strictly prohibited to modify and process blasting equipment in locations other than the processing room. When blasting equipment must be processed in the tunnel during long tunnel construction, the setting of the processing chamber should comply with the relevant provisions of the country's current "Blasting Safety Regulations" (GB6722-86).
2.2.3 Blasting operations and blasting equipment processing personnel are strictly prohibited from wearing chemical fiber clothing.
2.2.4 When blasting, all personnel should evacuate the site, and the safe distance is:
⑴ Single-ended tunnel is not less than 200m;
⑵ Phase The distance between adjacent upper and lower tunnels shall not be less than 100m;
⑶ The distance between adjacent parallel tunnels, cross passages and horizontal holes shall not be less than 50m;
⑷Full-section excavation for deep holes When blasting (hole depth 3-5m), the distance should be no less than 500m.
2.2.5 The number of blasts per day in the hole should be clearly defined, and the time between charging and blasting should not be too long.
2.2.6 Before charging, check whether the support near the blasting working surface is firm; the mud and stone powder in the blasthole should be blown clean; the heat of the newly drilled blasthole is too high, and charging should not be carried out immediately.
If there is insufficient lighting, if it is found that quicksand and mud flows have not been properly handled, or there may be a large amount of water gushing from the cave, charging and blasting is strictly prohibited.
2.2.7 Black powder is not allowed for blasting inside the hole.
2.2.8 It is strictly prohibited to ignite open flames when sparks are detonated. The length of the fuse should ensure that personnel can evacuate to a safe place after lighting the fuse, but it should not be shorter than 1.2m.
A blaster should not ignite more than 5 sticks at a time. If there are more than 5 guns fired at one time or when there are multiple people firing the guns, the timing fuse should be lit first, and the length of the timing fuse shall not exceed 1/3 of the length of the shortest fuse among the fuses to be lit. When timing After the fuse is burned, all blasters must evacuate the working surface regardless of whether the fuse is lit or not.
2.2.9 In order to prevent lighting interruption when firing, blasters should carry a flashlight with them and it is strictly forbidden to use open flames for lighting.
2.2.10 When using electric detonators for blasting, it must be carried out in accordance with the relevant provisions of the country's current "Explosion Safety Regulations" (GB6722-86)
and the power supply in the cave should be strengthened. Management to prevent leakage and explosion. Floodlights and miner's lamps can be used for lighting when charging. The main detonation wire should be installed in the air, and the distance from various conductors must be greater than 1m.
2.2.11 After 15 minutes of ventilation and smoke exhaust after blasting, inspectors can enter the working surface to check whether there is " "Blind gun" and suspicious phenomena; whether there are residual explosives or detonators; whether there are loose stones on both sides of the roof; whether the supports are damaged and deformed. Only after proper handling and confirmation can other staff enter the work surface.
2.2.12 When a "blind gun" is discovered, it must be handled by the original explosives personnel in accordance with regulations.
2.2.13 When loading cannons, wooden cannon sticks should be used to charge, and fire is strictly prohibited. Irrelevant personnel and machinery should be evacuated to a safe location.
2.2.14 When the two working surfaces are close to being connected, contact and unified command should be strengthened at both ends. The distance between the two working surfaces of a rock tunnel is close to 15m (20m for soft rock). When one end is charging and firing, the personnel at the other end should coordinate the firing time. Contact and vigilance should be strengthened before firing to prevent the other party's personnel from straying into the danger zone.
When connecting tunnels with broken soil or rocks, the safety distance reserved for the penetration should be appropriately increased according to the lithology. At this time, only one end is allowed to excavate, and the personnel and machinery at the other end should be evacuated to a safe location. The guide pit after penetration should be supervised by special personnel, and non-construction workers are strictly prohibited from passing through.
3. Transportation within the cave
3.1 All types of vehicles entering the cave must be in good condition, with effective braking, and mixed loading of people and materials is strictly prohibited.
3.2 All types of machinery and vehicles entering the hole should be powered by diesel engines with purification devices. Vehicles and machinery burning gasoline are not allowed to enter the hole (if the ventilation is good, the "ventilation and dust prevention" requirements of this chapter can be met Except those).
3.3 All transport vehicles are not allowed to be overloaded, over-width or over-height. When transporting large or extra-long materials, there should be dedicated personnel to direct the transportation, and red lights showing the boundaries should be set up.
3.4 People entering and exiting the tunnel should walk on the sidewalk and are not allowed to compete with machinery or vehicles. It is strictly forbidden to pick up cars, chase cars or force rides.
3.5 Ballast loading
3.5.1 When manually loading ballast, the vehicle should be stopped and braked. When the hopper is loaded with ballast, there should be a communication signal. When it is full, a stop leak signal should be sent, and the ballast leaking port should be covered in time. When collecting ballast, no one is allowed to pass under the funnel mouth.
3.5.2 When manually unloading ballast, the vehicle should be stopped and braked. It is strictly prohibited to stand in the truck to remove ballast.
3.5.3 When mechanically loading ballast, the cross-section of the tunnel should be able to meet the safe operation of the loading machinery. The cables or high-voltage hoses on the ballast loading machine should be retracted and released by dedicated personnel. When the ballast loading machinery is operated, the rotation range should be within the No one is allowed to pass.
3.6 Transportation within the tunnel
3.6.1 Rail transportation should comply with the following regulations:
⑴The radius of the flat curve in the tunnel should not be less than 7 times the wheelbase ; The outside of the hole should not be less than 10 times;
⑵ When transporting on two lines, the clear distance between vehicles should be greater than 0.4m, and the clear distance between vehicles and the pit wall or support edge should not be less than 0.2m.
⑶ During line transportation, a sidewalk with a width of not less than 0.7m should be set up on one side, and a staggered lane should be set up at an appropriate location, and its length should be able to meet the requirements of the longest train operation;
⑷The slope of the track in the tunnel should be consistent with the longitudinal slope of the tunnel, and an upward ramp of not less than 1 should be provided in the ballast unloading section;
⑸A vehicle blocking device and signs should be set up at the end of the line, as well as a sufficiently wide unloading platform. ;
⑹Transportation lines should be repaired and maintained by dedicated personnel, and waste and remaining materials on both sides of the lines should be cleaned up at any time.
3.6.2 Power-traction rail transportation operations may be handled with reference to the relevant provisions of the "Coal Mine Safety Regulations" (Ministry of Coal [86] Mei'an Zi No. 91).
3.6.3 Trackless transportation should comply with the following regulations:
⑴ The speed of transportation in the cave shall not exceed: 5km/h for rickshaws; 10km/h for motor vehicles in the construction area. 15km/h when towing a vehicle; 20km/h for a single vehicle in non-working areas, 15km/h when there is a tractor, and 10km/h when meeting vehicles;
⑵ Overtaking is strictly prohibited while the vehicle is moving;
⑶Set "slow moving" signs at tunnel entrances, level crossings and narrow construction areas, and assign dedicated personnel to direct traffic when necessary;
⑷Construction equipment and machinery parked close to the vehicle operation limit , a low-voltage red flashing light should be set on the outer edge to form a display boundary to prevent collisions of transport vehicles;
⑸ When reversing and turning in the cave, the lights must be turned on to sound the signal or a dedicated person can direct the vehicle;
⑹The area for unloading ballast outside the cave should maintain an uphill section, and a block should be set 0.8m within the edge of the ballast pile;
⑺The road surface should have a certain level of smoothness, and a dedicated person should be assigned Maintenance;
⑻ When vehicles meet or pedestrians pass through the cave, the large lights should be turned off and replaced with low beam or small lights.
3.7 Transportation of blasting equipment
3.7.1 When transporting blasting equipment outside a tunnel project, the "Regulations of the People's Republic of China and the Regulations on the Administration of Civilian Explosives" should be observed.
3.7.2 In any case, detonators and explosives must be transported separately in covered containers. When transported by manpower, detonators and explosives must not be transported by one person at the same time; when transported by car, detonators and explosives must be transported in two vehicles, and the distance between them should be more than 50m; when transported by rail vehicles, detonators and explosives should not be transported on the same train If they must be transported on the same train, the vehicles containing detonators and explosives must be separated by three empty carriages.
3.7.3 When transporting blasting equipment manually, there must be a special escort, and it should be delivered directly to the construction site without stopping in transit; the number of explosives transported by one person at a time must not exceed 20kg or one box of original packaging.
3.7.4 When transporting blasting equipment by car, a fireproof cover should be installed at the exhaust port of the car, and a red light should be displayed during operation. The equipment must be escorted by dedicated blasters, and other personnel are strictly prohibited from riding. The loading height of blasting equipment shall not exceed the edge of the carriage, and the loading height of detonators or nitroglycerine explosives shall not exceed the second floor.
3.7.5 When rail vehicles transport blasting equipment, their traveling speed shall not exceed 2m/s. Escorts and loading and unloading personnel are only allowed to ride in the tail car, and other personnel are strictly prohibited from riding. Nitroglycerin explosives or detonators must be placed in a special covered wooden carriage. The interior of the carriage should be paved with rubber or sacks and only allowed to be stacked in one layer.
3.7.6 It is strictly prohibited to use dump trucks, dump trucks, trailers, tractors, motor tricycles, human tricycles, bicycles, motorcycles and belt conveyors to transport blasting equipment.
4. Support
4.1 After excavation of all parts of the tunnel (including vertical shafts, inclined shafts, horizontal tunnels and parallel guide tunnels), except that the surrounding rock is intact and hard, and as specified in the design document Except for those that do not require support, effective support must be taken according to the surrounding rock conditions and construction methods.
4.2 During the construction period, the on-site construction leader should work with relevant personnel to conduct regular inspections of various support departments. In each section and shift of unfavorable geological areas, dedicated personnel should be assigned to inspect at any time. When deformation or damage to the support is found, it should be repaired and reinforced immediately; when deformation or damage is serious, construction personnel should be evacuated from the site first, and then reinforced.
4.3 The connection between the tunnel entrance section and the horizontal tunnel and auxiliary tunnel (cross tunnel, parallel guide tunnel, etc.) should be strengthened or permanently lined as early as possible. The support at the entrance of the cave should be supported by multiple 5∽8m open compartments outside the cave, and soil should be pressed on the top to stabilize the support. It can be dismantled only after the construction of the cave entrance is completed.
4.4 Support in the tunnel should be supported as the excavation is carried out. The distance from the support to the excavation surface should generally not exceed 4m; in the case of broken stone, severe weathering or soil tunnels, the support should be as small as possible. Protect the work surface. When work is stopped for a short period of time, the support should be placed directly against the working surface.
4.5 Support columns shall not be placed on rubble or movable stones. Columns in areas with weak surrounding rock should be equipped with pads or pad beams and tightly packed with wooden wedges.
4.6 When excavating the funnel hole, the support should be strengthened and a cover plate should be added; a solid escalator should be installed in the tunnel for people to go up and down.
4.7 When using wooden supports, hard and elastic wood such as pine and cypress should be used. The tip diameter of the beams and columns should not be less than 20cm, and the span should not be less than 25cm when the span is greater than 4m; other connecting rods should be slightly The diameter should not be less than 15cm, and the thickness of the board should not be less than 5cm. The wooden support should adopt a simple, upright, easy-to-dismantle and erect frame structure, and the transportation clearance of the tunnel should be ensured.
4.8 When installing steel brackets, small machines should be used for lifting, and the provisions of "Lifting and Hoisting" in this regulation should be followed.
4.9 When using shotcrete anchors for support, dangerous rocks should be removed, the scaffolding should be firm and reliable, and spray hands should wear protective equipment; all parts of the machine should be in good condition and the pressure should be maintained at about 0.2Mpa; the grouting pipe nozzle It is strictly prohibited to place it on people.
4.10 When it is found that the surrounding rock in the section that has been blasted has significant deformation or the anchor fails, additional reinforced anchors should be immediately added to the section, and its length should not be less than 1.5 times the length of the original anchor. times. If after blasting, it is found that the surrounding rock suddenly changes or the deformation of the surrounding rock exceeds the design allowable value, steel supports should be used for support.
4.11 When abnormal changes or mutations are found in the measurement data, the displacement value in the cave or on the surface is greater than the allowable displacement value, cracks appear in the cave or on the ground, and abnormal cracks appear in the spray layer and the spray layer, all should be considered. If there is a danger signal, workers must be notified immediately to evacuate the site, and construction can only continue after handling measures are formulated.
5. Ventilation and dust prevention
5.1 Tunnel operation environmental standards
5.1.1 Allowable dust concentration: per cubic meter of air, containing more than 10 free ions Silica dust must be less than 2mg.
5.1.2 Oxygen shall not be less than 20 (by volume, the same below).
5.1.3 Gas (biogas) or carbon dioxide shall not exceed 0.5.
5.1.4 Carbon monoxide shall not exceed 30mg/m3.
5.1.5 Nitrogen oxides (Converted into nitrogen dioxide) concentration should be below 5mg/m3.
5.1.6 The concentration of sulfur dioxide shall not exceed 15mg/m3.
5.1.7 The concentration of hydrogen sulfide shall not exceed 10mg/m3.
5.1.8 The concentration of ammonia It shall not exceed 30mg/m3.
5.1.9 The temperature in the tunnel should not exceed 28℃.
5.2 The air composition in the tunnel should be sampled and analyzed at least once a month; wind speed and dust content Test at least once a month.
5.3 Ventilation during tunnel construction should be managed by dedicated personnel. It should be ensured that 1.5∽3m3 of fresh air is supplied per person per minute.
5.4 No matter whether the ventilator is running or not, personnel are strictly prohibited from staying near the entrance and exit of the air duct. When the ventilator is stopped, no one is allowed to approach the ventilation soft air. Walk and stay near the hose and do not place anything on the vent pipe or opening.
5.5 During construction, it is advisable to use wet rock drill drilling, water seal blasting with water cannon mud, wet spray concrete spraying and other construction techniques that are beneficial to reducing dust concentration.
5.6 The following dust prevention work should be done on rock drilling and ballast loading working surfaces:
⑴ Spraying and watering should be carried out before and after blasting;
⑵ Ballast removal Water should be used to drench the slag pile and wet the rock wall before use;
⑶A sprayer should be placed at the blowing-type air outlet.
5.7 The solid content of dustproof water should not exceed 50mg/L, and the E. coli should not exceed 3/1. The pool should be kept clean and have sedimentation or filtration facilities.
6. Lighting, drainage and fire prevention
6.1 Lighting
6.1.1 The lighting in the tunnel should be maintained with sufficient brightness, uniformity and no flickering. It should be based on Different heights are selected for the size of the excavation section and the location of the construction working surface.
6.1.2 Moisture-proof insulated wires should be used for electrical lines in the tunnel, and should be hung firmly with porcelain bottles at the specified height. Do not hang wires on nails or other iron objects, or bundle them together. A wooden box cover should be added to the switch and a closed fuse box should be used. If cables are used, they should be hung securely at a high place and should not be placed on the ground.
6.1.3 The lighting voltage of each part of the tunnel should be:
⑴ 12∽36v for excavation, support and lining operations;
⑵ Completed tunnel The section is 110∽220v;
⑶The portable work light is 12∽36v.
6.1.4 The power lines and lighting equipment in the tunnel must be assigned a dedicated person to be responsible for maintenance management and circuit maintenance. The power supply should be cut off when working with lighting equipment.
6.1.5 Electric lamps in damp and leaky tunnels should use waterproof lamp sockets.
6.2 Drainage
6.2.1 In tunnels with groundwater discharge, drainage ditches must be dug. When excavating downhill, a water inflow volume greater than 20 should be set according to the amount of water inflow. Pumping equipment is used to drain the water. The installation location of the pumping machinery should be on one side of the guide pit or in a separate hole, and should be isolated from the tunnel by a fence.
6.2.2 Electric machinery should be used for water pumping equipment, and internal combustion water pumps are not allowed to be used in tunnels. There should be a certain number of spare units for pumping machinery.
6.2.3 If tunnel excavation is expected to pass through water-gushing strata, advance drilling should be used to detect water and find out the thickness, lithology, water volume, water pressure, etc. of the aquifer to provide a basis for preventing and controlling water-gushing. .
6.2.4 If a large amount of water is discovered on the working surface, workers should immediately stop working and evacuate to a safe location.
6.3 Fire Prevention
6.3.1 Effective and sufficient fire-fighting equipment should be installed in each cave, wellhead construction area, mechanical and electrical chambers, material warehouses, belt conveyors, etc. in the cave. Obvious signs should be set up for regular inspection, replenishment and replacement, and should not be used for other purposes.
6.3.2 Weeds within 20m of the hole entrance must be removed. The fire source should be at least 30m away from the hole. Fireworks are strictly prohibited within 20m of the warehouse. Open fire operations and heating are strictly prohibited in the cave.
6.3.3 Gasoline, kerosene, transformer oil and other flammable items are not allowed to be stored in the cave and in each chamber. Cleaning of pneumatic tools should be done in a dedicated chamber with an outward-opening fire door.
7. Gas prevention and control
7.1 When gas is found during tunnel construction, ventilation should be strengthened and preventive measures should be taken. When the gas concentration in the tunnel still exceeds the provisions of Article 5.1 of this regulation after ventilation When doing so, the provisions of this section shall be followed.
7.2 Gas prevention and control is mainly to eliminate gas excess and accumulation, and to cut off all fire sources that may ignite gas explosions.
7.3 It is strictly prohibited to use oil lamps, carbide lamps, gas lamps and other flame-burning lights in the tunnel. Anyone entering the tunnel must undergo inspection and it is strictly prohibited to bring matches, lighters and other items that may spontaneously ignite into the tunnel.
7.4 Electric lighting
7.4.1 The voltage shall not exceed 110V;
7.4.2 Sealed cables must be used for power transmission lines;
7.4 .3 Lamp holders, switches, bulbs and other lighting equipment must be explosion-proof, and switches must be installed in air supply ducts or openings.
7.5 Miner's Lamp Lighting
7.5.1 The total number of intact miner's lamps standing at each cave entrance should be greater than 10 of the total number of people who regularly use the lamp.
7.5.2 Miner's Lamp They all need to be numbered, and those who use miner's lamps should have fixed lamp numbers.
7.5.3 Mining lamps are strictly prohibited if they have battery leakage, insufficient brightness, damaged wires, poor lamp locks, loose lamp head seals, loose lamp head rings, broken glass and plastic shells, etc. The miner's lamp that emits light should be able to be used normally for at least 11 hours continuously.
7.5.4 Personnel using miner’s lamps should strictly not dismantle, knock or impact the miner’s lamp. When leaving the cave or leaving get off work, the miner's lamp should be returned to the lamp room immediately.
7.6 When the gas concentration in the wind flow of the excavation working face reaches 1, the electric drill must be stopped to drill holes; when it reaches 1.5, the work must be stopped, and personnel must be withdrawn to cut off the power supply and deal with it.
When the gas concentration in the wind flow reaches 1 within 20m near the blasting site, it is strictly prohibited to charge and blast. When the gas concentration in the air flow within 20m near the motor reaches 1.5, the power must be cut off to stop operation. When the local gas accumulation concentration in the excavation working face reaches 2, the work within 20m nearby must be stopped and the power supply must be cut off.
7.7 Electrical equipment whose power supply is cut off due to exceeding the gas concentration regulations must be started when the gas concentration drops below 1; excavation working surfaces using automatic gas detection and alarm power-off devices can only be restored to power manually. .
7.8 Tunnel blasting operations
7.8.1 It is strictly forbidden to use spark detonation and exposed blasting;
7.8.2 When blasting, it is advisable to use instantaneous detonators. When using millisecond detonators, the total delay time shall not exceed 130ms. It is strictly prohibited to use second and half-second delay electric detonators;
7.8.3 Use coal mine safety explosives;
7.8.4 When blasting in a short tunnel, all personnel must evacuate outside the tunnel; in a long tunnel, the single line should be evacuated 300m away, the upper half-section excavation of a two-lane tunnel should be evacuated 400m away, and the full-section excavation of a two-lane tunnel should be evacuated 500m away.
7.9 Machinery in gas tunnels, such as battery carts, ventilators, telephones, blasters, etc., must be explosion-proof.
7.10 Wet rock drilling must be strictly used, and the metal hammer head used in the hole must be inlaid with a non-sparking alloy. The metal instruments used for loading ballast must not collide with the stone ballast violently, and the stone ballast must be wetted before loading.
7.11 When installing and repairing various electrical equipment in the cave, the power supply must be cut off first. Cable interconnection or branching must be soldered, insulated and wrapped outside the hole and hot patched. It is strictly prohibited to temporarily connect lights or other equipment to cables in the cave. When the cables are connected in the hole, they should be connected in a special explosion-proof junction box or an explosion-proof junction box.
7.12 For tunnels with gas, a full-time gas inspector must be stationed at each entrance. Testing is normally performed every hour and the results are recorded in the record book. The gas detector should be calibrated quarterly.
7.13 Ventilation must be of the blow-in type. The ventilation host should have a backup machine and should be powered by two power supplies. When the ventilator stops, all personnel in the cave must evacuate outside the cave.
7.14 All operations that can cause high temperatures and sparks are strictly prohibited in the tunnel.
7.15 Necessary first aid and rescue equipment and personnel must be used during tunnel construction. Construction workers must have safety knowledge to prevent gas explosions.
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