为了提高钻孔桩承载能力,可以采用钻孔时孔头扩大,也可采用爆破法使桩头扩大,现浇混凝土桩二次复打也能提高承载能力等。在现浇混凝土灌注桩中,钻孔时一般要求不加水或少加水,这样原状土的含水量尽量保持原来的状态,就使钻进速度减慢。若加水就增加了润滑剂,但桩承载力降低。 In order to improve the bearing capacity of the bored pile, the hole head can be enlarged during drilling, and the pile head can also be expanded by the blasting method. In-situ concrete piles can also increase the bearing capacity when they are double-fighted. In cast-in-situ concrete cast-in-place piles, it is generally required that no water be added or less water is added during drilling, so that the water content of the undisturbed soil is kept as much as possible and the drilling speed is slowed down. If water is added, lubricant is added, but the bearing capacity of the pile is reduced.