Drilled piles are usually constructed by drilling rigs.
(1) The drilling rig is set up so that the center of the drilling rods coincide, and its horizontal displacement and tilt error are adjusted according to the specification requirements.
(2) When drilling with an impact drill, the drill should be started only when the concrete that has been filled on the neighboring holes has solidified and has reached a certain strength.
(3) The drilling process adopts the positive cycle rotary drilling construction technology, in the clay layer, the appropriate less mud, rely on the drilling of their own slurry, in the sandy layer is to increase the concentration of slurry solid wall. The drilling speed is always compatible with the amount of mud discharged.
(4) The hydrostatic pressure of 0.2kg/cm? is always maintained in the hole, and the water level in the shroud is always higher than the water level of the reservoir. When encountering loose strata, the relative density and consistency of the mud will be increased appropriately to minimize the impact of the flushing liquid on the hole wall, and the rotational speed and the drilling pressure will be reduced to meet the requirements of the quality control of the construction.
(5) During the drilling process, it is strictly prohibited to drop the drill bit, drill pipe and other foreign materials into the hole, and the wear of the drill bit is checked frequently.
Expanded Information
Precautions for filling concrete:
(1) The slump of concrete is 18～22cm, and the particle size of coarse aggregate is less than 40mm.
(2) Concrete filling is carried out within 30 minutes immediately after the end of the second clearing of holes.
(3) Φ250 flanged conduit is used for self-flowing concrete filling. The conduit coupling should be straight and sealed reliably; the lower mouth of the conduit is 30cm to 50cm from the bottom of the hole.
(4) the first tray of pouring: the initial filling volume must ensure that the bottom of the conduit buried in the concrete more than 80cm, and continuous filling.
(5) normal pouring of concrete, the bottom of the conduit buried in the concrete depth of 2 to 6m.
(6) One time dismantling conduit shall not exceed 6m, each time before dismantling the conduit should measure the height of the concrete surface, calculate the depth of the conduit, and then dismantle. Do not blindly lift and dismantle the conduit, the minimum depth of the conduit is 2.0m.
Baidu Encyclopedia-Bored Pile