Nowadays, the construction of large buildings is becoming more and more common. The increase in the scale of buildings has higher and higher requirements for the quality and safety of foundations and pile foundations. Today, the editor has collected and sorted out the safety points in the construction of various pile foundations to share with you. share.
1. Safety requirements for construction of squeezed soil piles and partially squeezed soil piles
The construction of squeezed soil piles and partially squeezed soil piles generally includes driven pile construction, vibration sunk pile construction, static pressure-driven pile construction, vibrating pile construction, rotary grouting pile construction, etc. The main safety precautions during the construction process are as follows :
(1) Pile driver operators should undergo training and examination and obtain an operation certificate before they can start working.
(2) The construction site should be leveled and compacted. There should be no high-voltage lines within 5m around the pile driver. There should be obvious signs or fences in the work area, and no idlers are allowed to enter.
(3) When moving the pile frame, the pile hammer should be placed at the lowest position. The movement should be slow and under unified command, and measures should be taken to prevent tipping.
(4) The wire rope of the piling machine winch should be in a lubricated state to prevent dry friction. The use and scrapping standards of the wire rope should be implemented by the specification “Practical Specification for Inspection and Scraping of Wire Ropes for Hoisting Machinery” (GBT5912).
(5) The pile driver should be inspected before the operation to ensure that the equipment is intact, the bolts are tight and the safety devices are effective before starting.
(6) The electrical equipment of the pile driver should be well insulated and should be grounded (or grounded) for protection. The power cable should be retracted and released by a dedicated person and must not be dragged and dropped anywhere.
(7) During operation, if the downtime is long, the pile hammer should be dropped and padded. It is strictly prohibited to suspend the pile hammer for maintenance.
(8) The operation of the pile driver during the construction process should be strictly carried out following the safety regulations “Technical Regulations for Safety in the Use of Construction Machinery” (JGJ33).
(9) Operations should be stopped in severe weather such as strong winds of level 6 and above, thunderstorms, heavy fog, heavy snow, etc.
(10) When the wind exceeds level 7 or there is a severe tropical storm warning, the pile driver should be parked in the wind direction and a winding rope should be attached. If necessary, the pile frame should be lowered to the ground.
(11) After the operation is completed, the pile driver should be parked on solid and flat ground, brake and wedge firmly, and cut off the power supply.
2. Safety requirements for manual digging pile construction
Manually dug pile operations refer to the reinforced concrete piles that are excavated manually and poured on-site. It is mostly used in dense soil or weathered rock formations with no or a small amount of groundwater. It is also used in areas where mechanical hole formation cannot be used or where mechanical hole formation is difficult and hydrological and geological conditions permit. It is the main method in the construction process of manually dug piles. Things to note are:
(1) Construction workers should wear labor protection supplies. Workers working on the surface at the hole entrance must wear safety belts, and workers working at the bottom of the well must wear safety helmets.
(2) Before and during every day of construction, a comprehensive inspection of the machinery and tools put into use must be carried out. Lifting equipment should be equipped with necessary safety devices, and the machinery and tools must be maintained after construction.
(3) When there are people at the bottom of the hole, there must be someone on the ground to monitor them. During the operation, the upper and lower personnel work alternately. There should be necessary communication equipment and devices between the bottom of the hole and the workers on the ground to keep in touch at all times.
(4) Safety guardrails must be installed around dug pile wells, and safety warning signs should be installed in the work area. No idle personnel are allowed to enter the construction area.
(5) There should be sufficient lighting in the nighttime construction work area. Pile holes where construction is suspended must be sealed with covers. Obvious warning signs must be set up when necessary, and red warning lights must be set up in dangerous places at night.
(6) The first section of the protective wall should be 300mm higher than the ground level to prevent surface water, spoil, debris, etc. from falling into the hole.
(7) When the hole is dug to a depth of less than 5m, a semicircular safety shield should be installed on the flange of the protective wall about 3m from the bottom of the well. When slag is discharged, the operator in the hole should be under the shield.
(8) During the construction process, the construction process should be strictly controlled according to the plan and design requirements, and each section should not exceed 1m. Support should be provided promptly after excavation, and each section of the protective wall should be completed continuously on the same day.
(9) When water seepage from the well wall is encountered during excavation, the water should be drained in time. When the amount of water is not large, use a bucket to transport it out. When there is a large amount of water seepage, dig a water collection pit at the bottom of the hole and use a submersible pump to drain the water. , and pour the concrete retaining wall immediately.
(10) The excavated earth should be transported away from the hole in time and should not be piled within 5m of the hole.
(11) Pile holes with a depth greater than 10 meters should have air supply devices, and the air should be supplied 5 minutes before each start of work; if there are toxic and harmful gases in the hole, ventilate for 15-30 minutes, and then re-detect the gas until the gas concentration Until the requirements for safe operation are met, good ventilation should continue to be ensured during operation.
(12) During construction, air should be continuously supplied into the hole. The air supply volume should be greater than 25L per second. The air supply pipe should be bent as little as possible to ensure a smooth air supply. The hose should be checked frequently for air leakage. Once damage is found, it should be repaired and blocked at any time. leak.
(13) Waterproof bulbs with covers should be used for lighting in the hole, with a voltage of 12V and below, and the cables should be waterproof insulated cables.
3. Safety requirements for bored pile construction
Bored cast-in-place piles are piles formed by mechanically drilling holes into the foundation, placing steel cages in the holes, and pouring concrete. The main precautions during the construction process of bored piles are:
(1) On-site personnel must wear various safety protective equipment, and special operations personnel must hold certificates to work.
(2) Mechanical equipment must be inspected, repaired, and maintained before construction. Cables used in construction must be carefully inspected and used only after they are confirmed to be safe.
(3) Concrete pouring and crane lifting must be directed by dedicated personnel. All live equipment must be powered off before moving. Illegal operations and work without a license are strictly prohibited.
(4) All electrical equipment must have good grounding, the grounding resistance should not be greater than 4Ω, and be equipped with reliable electric shock protection devices. Distribution boxes and other power supply equipment must not be placed in water or mud. Wire joints must be firm and insulated. Transmission lines must be equipped with leakage switches.
(5) Before unloading materials (mainly steel bars, steel plates, and steel pipes) on-site, you must check whether there is anyone in the unloading direction to avoid injuring people.
(6) The operation site must be managed in a closed manner, with fences and warning signs set up around the openings and mud pools, and irrelevant personnel are strictly prohibited from entering the site.
(7) Before installing the drilling machine, you should master the exploration data and confirm that the geological conditions meet the requirements of the drilling machine. There are no buried objects underground, there are no obstacles within the operating range, and the safety distance between the construction site and overhead transmission lines meets the requirements.
(8) When installing the drilling machine, the foundation of the drilling frame of the drilling machine should be compacted and leveled. Sleepers should be laid under the drilling frame of the tire-type drilling rig to raise the tires. After the drilling rig is raised, the whole machine should be kept in a horizontal position.
(9) During drilling, the operation of the drilling rig should be observed at any time. When abnormal noises, broken slings, air leakage, slag leakage, and other abnormal conditions occur, the machine should be stopped immediately for inspection. Only after the fault is eliminated can the operation continue. Drill.
(10) During the drilling process, the water level in the casing should always be kept at least 50cm higher than the bottom of the casing to prevent hole collapse.
(11) When the drilling rig is in operation, a dedicated person should be assigned to direct and operate it. Others are not allowed to board the rig at will; operators are not allowed to leave their posts without authorization while on duty.
(12) Stop drilling, lift the drill bit out of the hole, and place it on the drill frame. It is strictly forbidden to leave the drill bit in the hole for too long.
(13) When constructing near high-voltage lines or business lines, measures should be taken to prevent electric shock and equipment overturning.
(14) The relocation and disassembly of the drilling rig should be carried out under the instructions. Ensure that the drill pipe and other movable parts are firmly fixed before proceeding. During the transfer and disassembly process, collisions with the machine frame should be prevented.
(15) During night construction, sufficient lighting must be provided. When the work site is located next to a road or in an area with frequent human activities, clear signs must be hung during the day and sign lights must be hung at night.
(16) After operation, the drilling rig should be cleaned and lubricated, and the main parts should be properly covered.
(17) Drilling operations should be stopped when there are strong winds, heavy fog, rain, or snow of level 6 or above.
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