Concrete, concrete admixtures, and additives: Retarders and fly ash should all meet the relevant standard requirements, and their dosage should be determined by laboratory testing according to construction requirements.
The mix proportions must be strictly followed when preparing the mixture.
The slump for auger drilling and in-pipe pump-pressed concrete pile construction should be 160-200 mm; the slump for vibratory driven cast-in-place pile construction should be 30-50 mm. The thickness of the slurry at the top of the pile after vibratory driven cast-in-place pile construction should not exceed 200 mm.
After drilling to the design depth, the timing of pulling up the drill rod should be accurately controlled for auger drilling and in-pipe pump-pressed concrete pile construction. The pumping rate of the mixture should be coordinated with the pipe pulling speed. Pumping should not be stopped to wait for material when encountering saturated sand or silt layers. The pipe pulling speed for driven cast-in-place pile construction should be controlled at a uniform speed, approximately 1.2-1.5 m/min. If encountering silt or silty soil, the pipe pulling speed should be appropriately slowed down.