Rotary excavation pile refers to the pile type constructed by rotary drilling rig, which is called rotary drilling cast-in-place pile in full name and referred to as rotary excavation pile in engineering.
It is an advanced pile foundation construction technology popularized and used in China in recent years. It is widely used in foundation pile construction of highways, railways, bridges and large buildings. Most of the early rotary drilling rigs were imported from Germany and Italy, or used by Japanese rotary drilling rigs. In recent years, with the promotion of Qinghai-Tibet Railway, Beijing Bird's Nest and other projects, foreign brands are pouring in, and domestic similar products are gradually developing.
Matters needing attention in the construction of rotary excavation supporting piles in construction enterprises;
(1) All equipment, facilities, safety protection devices, tools, accessories and personal protective equipment on the construction site must be inspected frequently to ensure that they are in good condition and used correctly.
(2) When lighting is needed for the operation in the pile hole, safe voltage must be used, lamps and lanterns should meet the explosion-proof requirements, and cables in the hole must be fixed to prevent damage and moisture.
(3) It is forbidden to dig holes manually at night.
(4) The excavation sequence of each pile on the same pier depends on geological conditions, pile position arrangement and spacing. The pile spacing is large, so it can be excavated diagonally, otherwise it can be excavated in a single hole.
(5) Workers in the hole must wear safety helmets, and smoking, wearing chemical fiber underwear or using open flames are not allowed in the hole. The same person shall not work continuously in the hole for more than 2 hours.
(6) Before shift and during construction, check whether all parts of lifting equipment are firm and flexible at any time; Whether the legs are firm and stable; Whether the hoisting wire rope and its connection with the hook, the safety buckle of the hook and the anti-falling protection device are firm and reliable; Whether the bucket is in good condition, repair or replace it in time when problems are found.
(7) The principle of subsection construction must be observed, that is, a section of soil must be dug and a section of concrete retaining wall must be made. The excavation in the hole must be carried out after the retaining wall is stable.
(8) In the pile hole under construction, the accumulated water shall be discharged before the shift every day, and the hole shall be blown with a blower for at least 5min. Only after the pile hole meets the requirements can it be operated manually. When the carbon dioxide concentration exceeds 0.3% or the hole depth exceeds 10m, the ground should be equipped with special equipment to supply air to the hole, and the air volume should not be less than 25L/s, and the air volume should be increased when drilling at the bottom of the hole.
(9) There is someone working in the hole, and the orifice should be supervised by special personnel. When deformation of the retaining wall, water gushing, quicksand and gas with peculiar smell are found, the operation shall be stopped immediately, and the workers in the hole shall be evacuated to the ground quickly, and reported to the person in charge of construction for treatment. After the hidden dangers are eliminated, the construction can continue.
(10) When excavating complex soil structure, every 0.5m or not less? 16 The rebar shall undergo tortuous exploration at the bottom of the hole, check whether there are caves and sand gushing below the bottom of the hole, and continue the operation only after it is confirmed to be safe.
(1 1) A safe and reliable ladder should be used for the operators to go up and down the hole. It is not allowed to use artificial ropes to transport the operators and step on the retaining wall flange to go up and down the pile hole. The inner wall of the pile hole should be provided with nylon safety rope (tie a knot every 30cm or so), and extend to the working face with the increase of excavation depth as an emergency standby.
(12) Tools required for pile hole operation shall be transported in barrels. The heavy end of the long-handled tool should be placed at the bottom of the barrel, and the upper end should be tied to the lifting rope with a rope. It is forbidden to throw into the hole, and it is forbidden to mix tools and earthwork for lifting.
(13) When the depth of the pile hole is less than 5m, a semi-circular protective cover shall be set on the retaining flange at the bottom of the hole about 3m. The protective cover can be made of wooden boards. When the excavated earth bucket is transported up and down, the workers in the hole must stop working and stand under the protective cover. When lifting a big stone from the pile hole, no one is allowed in the hole. After loading the object, the workers in the hole must reach the ground before lifting it.
(14) When drilling at the bottom of the hole, wet operation method should be adopted, and the air supply must be increased. Workers must wear insulating shoes and gloves. Power consumption of drilling tools must comply with relevant regulations.
(15) Submersible pump should be used to clear the accumulated water in the hole, internal combustion engine should not be used as drainage power, and no one should be in the hole during drainage. After the drainage operation, the operator must cut off the power supply of the submersible pump before entering the hole.
(16) The excavated earthwork shall be transported away in time, and sundries or excavated earthwork shall not be piled up within 3m around the pile hole.
(17) Motor vehicles need to pass through the job site, so safety protection measures must be formulated and their driving routes must be specially planned. When a motor vehicle is driving on the construction site, no one is allowed to work in the pile hole near its driving route.
(18) A drainage system should be set on the ground of the orifice to prevent the accumulated water from being reinjected into the hole. If there is mud near the orifice, it must be cleaned up in time.
(19) When stopping operation in the hole, it is necessary to cover the orifice or set a protective railing not less than 1.2m, close the orifice with sufficient strength, wrap a protective net on the fence, set up eye-catching warning signs, and set up a red light warning at night.
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