3, drilling,

(1) Check the perpendicularity of the cylinder:The rig is in position and the fuselage is adjusted. Two theodolites are used to check the verticality of the guard cylinder in the vertical direction.

(2) Before drilling the first pile, the hopper and pipeline of the concrete pump should be wet with water, and then pumped with mixed cement mortar(Lubrication piping )And seal the drill hole valve after pumping all mortar out of the pipe.

(3According to the designed pile length, determine the drilling depth and mark the corresponding position of the drilling tower as the basis for controlling the pile length during construction.

(4) After the pile machine is in position, draw a circle with the same diameter as the guard cylinder with the pile site as the center. Before drilling, after the vertical degree of the guard cylinder and the circle is adjusted, the guard cylinder begins to drill, and the vertical degree is controlled while drilling.

(5) Control the verticality while drilling at the guard cylinder, and wait for the guard cylinder to drill2-3m, the casing stops drilling, and the long auger begins to drill below the casing mouth 500mm , the guard cylinder and auger drill synchronously to the designed elevation.

(6During the drilling process, the drilling speed should be strictly controlled. When just touching the surface, the drilling speed should be slow. The rate of drilling should be determined according to the soil condition:Miscellaneous fill soil, clay soil should be controlled in 0.5-1.0m/min, plain fill soil, clay, silt, sand should be controlled in1.0-1.5m/min .

(7) In case of stuck drilling, rig shaking, deviation or rhythmic sound in the drilling process, stop drilling immediately, find out the reason, and take corresponding measures before continuing the operation.

(8Keep the auger and casing synchronized during drilling.

(9In the construction process, the Construction Record Form of undisturbed earth taking and pressurized concrete Pile with full protective cylinder should be filled in timely and accurately.

4Pump concrete

After the guard drum and drill bit reach the designed elevation, keep the guard drum still and lift the drill pipe200mm, start pumping concrete, pumping concrete should pay attention to the following points:

(1(Concrete pumping should be carried out continuously to avoid insufficient feed and shutdown waiting for feed caused by slow feed on the back platform;

(2) pump concrete to reach1mAfter the height, start to lift the drill, pump the concrete while lifting the drill, and control the lifting rate to match the pumping quantity;

(3(In the process of piling, the exhaust valve must be ensured to work normally to prevent pipe blocking in the process of piling;

(4) The height of the concrete surface in the hopper should always be maintained at least during pumping400mm, in case of pipe blockage caused by air inhalation.

5, concrete preparation requirements

The pumped concrete shall meet the following requirements:

(1) The supply station must provide "ready-mixed Concrete Quality Certificate" and concrete grading list;

(2) The initial setting time of concrete should not be less than6Hours.

(3) Concrete collapse degree:180-220mm;

(4) The amount of concrete cement should not be less than260kg/m³;

(5) appropriate choosesP.O 42.5Cement;

(6) should be selected clean sand, mud content is not greater than3%;

(7) stone should be selected hard particle size5-20mm Of bean stone or gravel, the mud content is not greater than 2%;

(8) The concrete of the commodity entering the site should have good workability and fluidity, and the slump loss should be able to meet the perfusion requirements;

(9) The concrete entering each vehicle should be tested for its collapse degree.

6Concrete pipe requirements

(1(The steel pipe and high-strength flexible pipe connecting the concrete conveying pump with the drilling rig should not be less than the inner diameter125mm;

(2Before construction, the sealing of the connection of the pipeline should be checked. The test method is:Close the concrete outlet valve and pump tap water according to the pumping pressure of normal concrete pumping. If the pipe connection is not leaking, the pipe connection is in good condition ;If there is a leakage point, the leakage point of the joint card for strengthening treatment, until the leakage point disappears;

(3) An arc-shaped steel pipe should be hung in the middle of the rig as a transition joint, and flexible pipes should be connected at both ends to reduce the amount of pipeline movement.

7, steel cage production requirements

(1) The specifications and quality of the steel bars shall meet the design requirements, and the warranty shall be attached. Raw materials shall be sampled and submitted for inspection according to the construction code.

(2) Before making the steel cage, straighten the main bars, remove the dirt and rust on the surface of the steel bar, and accurately control the length of the steel bar.

(3) The steel cage shall be made of ring mold;

The steel cage should be made as a whole according to the design length;The main reinforcement and reinforcement should be spot welded firmly, and the main reinforcement should not be damaged;using E43and E50Type D welding rod for welding.

Allowable deviation:

The primary spacing±10mm; Stirrup spacing±20mm;

Diameter of the steel cage±10mm; The length of the steel cage±100mm;

Protective layer deviation is controlled in20mm Or less.

(4) The main bar of the steel cage is connected by electric welding. When single-sided welding is used, the binding length should not be less than10D( DRepresents the diameter of the main rib );When double-sided welding is used, the binding length should not be less than5D .

(5) The number of joints in the same section shall not be greater than the total number of main reinforcement50%, adjacent joints should be staggered up and down, staggered distance should not be less than 1m;

(6) The steel cage shall be made as a whole and processed into a conical pile body, and the total length shall be consistent with the designed pile length;

(7) The steel cage can be used after it is processed and qualified by supervision inspection;

(8After the steel cage is made, it should be placed on the clean ground to avoid being polluted by soil and oil stains;

(9The steel cage shall be covered in rain or snow.

8, steel cage lifting

(1(The lifting of steel cage should be adopted four points lifting, and should ensure straight lifting;

(2) After the cage is removed from the ground, the principle of gravity shift is used to convert the flat lifting into vertical lifting by lifting the pulley of the wire rope on the crane trench, so as to facilitate the entry of the hole;

(3) each lifting point should be strengthened to prevent the cage from being too heavy and deformed;

9And the insertion of steel cage

(1) The reinforcement cage should be inserted immediately after the pile is perfused and cleaned;

(2) The reinforcement cage should be aligned with the hole before insertion, and ensure that it is vertical and centered;

(3) The reinforcement cage should be continuously lowered, should not stop, the direct decoupling method is prohibited when lowering;

(4) When inserting the steel cage, first rely on the dead weight of the steel cage and feeding bar slowly inserted, when relying on the dead weight can not continue to insert, open the vibration device, so that the steel cage sink to the design depth, disconnect the connection between the vibration device and the steel cage, slow continuous vibration pull out the feeding bar.

10Requirements for pulling out the guard cylinder

(1) The protective cylinder should be pulled out after the reinforcement cage is inserted;

(2) The guard cylinder should be pulled out slowly while rotating.

Shanghai Qiangqiang Foundation Engineering Co., LTD. 's business covers foundation pit engineering, pile foundation engineering, land and waterFoundation treatment , slope treatment and other engineering fields. around "Excellent technology, reliable process , quick construction"Technical requirements,   Is to provide customers with land, water foundation engineering technical consultation, construction services and other comprehensive solutions of the entity enterprise.  Contact Number:400-1002850