2 concrete quality inspection witness commercial concrete certificate, alkali content evaluation report materials.
3 reinforcing cage spacing, diameter and length of the builder's acceptance visa
4. The builder shall check the accuracy of the pile position at the stop point of the pile position.
5 Borehole Depth Acceptance Visa Stop Point Borehole Depth Builder
6 construction original record visa witness original record inspector
4 construction methods and quality standards
4. 1 Measure and set out, determine the pile position, dig mud ditch and mud pool, and bury the casing. Steel liners are used, the deviation between the center and the center of the pile position is not more than 50 mm, the upper opening of the liners is higher than the ground 150mm, the inner diameter is larger than the drill bit diameter 100mm, and the upper part is provided with 1 ~ 2 slurry outlet holes. The height of casing shall meet the requirements of the height of mud surface in the hole (the surface soil layer is good, and the hole will not collapse after drilling, so casing may not be buried).
4.2 After the drilling rig is in place, it must be stable to ensure that it does not tilt or shift during construction. In order to accurately control the drilling depth, it is necessary to make a scale to control the depth on the frame for observation and recording during construction.
4.3 Before spudding, it is necessary to ensure smooth mud discharge and ready mud transportation.
4.4 Water injection pipes and drilling rig cables shall be handled by special personnel and straightened with the lifting of drilling rig.
4.5 Before drilling, the drilling rig must be filled with water, and the penetration rate should be controlled at 0.2m/min. When hard soil is encountered, the drilling speed should be slowed down appropriately, and the drilling speed of the drilling rig should not exceed the load. When the drilling speed of the drilling rig reaches the designed hole depth, the drilling rig will idle without drilling and inject water at the same time. When the residue at the bottom of the hole is ground into mud, and the specific gravity of the drainage mud is reduced to about 1. 1, it can be considered that the hole cleaning is qualified by twisting the mud with fingers without sand.
4.6 Before the end of hole cleaning, the mud index should be determined to ensure that the sediment at the bottom of the hole is not greater than the allowable thickness when pouring underwater concrete. After hole cleaning, underwater concrete construction shall be organized immediately, generally within one hour from the stop of hole cleaning to the start of concrete pouring.
4.7 After the pile is completed, the depth and aperture must be measured, and concrete can be poured only after it meets the design requirements.
4.8 Before pouring concrete, the specific gravity of mud at the bottom of the hole should be less than1.25; Sand content is less than or equal to 8%;
Viscosity ≤ 28s; The thickness index of sediment at the bottom of the hole meets the design requirements and shall not be greater than 200 mm.
4.9 In the process of drilling, if inclined holes, collapsed holes and slurry leakage around the casing are found, drilling should be stopped and drilling should be carried out after corresponding measures are taken. In case of necking and hole collapse, the specific gravity of mud can be increased to stabilize the hole and protect the wall, and clay and mud paste can also be put in the necking and hole collapse section; Let the submersible rig idle, there is no footage to fix the wall. In case of serious necking, hole collapse or sudden slurry leakage, clay should be backfilled immediately, and drilling should be carried out after the hole wall is stable.
4. 10 pouring underwater concrete shall comply with the following provisions:
A. When pouring concrete, the distance from the bottom of the conduit to the bottom of the hole should be 300 ~ 500mm in order to make the waterproof plug discharge smoothly;
B there should be enough concrete reserves to make the conduit buried below the concrete surface for more than 0.8m at a time;
C the buried depth of conduit should be 2 ~ 6m. It is forbidden to raise the concrete surface of the conduit. The buried depth of the conduit and the elevation difference of the concrete surface inside and outside the conduit shall be measured by special personnel, and the underwater concrete pouring record shall be filled in.
D. Underwater concrete must be continuously constructed, and the pouring time of each root should be controlled according to the initial setting time of the initial concrete slab, and all faults in the pouring process should be recorded for the record;
E, control the last pouring amount, the pile top shall not be low, and the gouging height must ensure that the exposed pile top concrete reaches the strength design value.
4. 1 1 underwater riser construction is used for concrete pouring, which is characterized by self-gravity extrusion of concrete and continuous pouring from bottom to top, so it requires good workability and high slump.
Drill holes, run pipes and watch pumps at the front desk; Motorized dumper driver; Welded reinforcing cage; Construction management personnel; The number is quite large.
Underwater engineering operation is an underwater engineering task.
Construction personnel (divers) finish underwater, shoot underwater video and send it to the shore in time. The supervision engineer can know and check the construction situation at any time according to the video, and find and solve the existing problems at any time.