Mud circulating method and circulating system for cast-in-place pile construction

The invention discloses a mud circulating method and a circulating system for cast-in-place pile construction. The mud circulating method and the circulating system are applied in construction of direct and reverse circulating drilling cast-in-place piles. According to the mud circulating method disclosed by the invention, mud used for drilling casting is communicated with a mud pool and a drilling machine mud circulating pipeline through a ground circulating pipeline to construct the mud circulating system. The mud circulating system disclosed by the invention comprises the drilling machine mud circulating pipeline and the mud pool, wherein one end of the drilling machine mud circulating pipeline is communicated with a drilling machine, and the other end of the drilling machine mud circulating pipeline is communicated with a mud pump in the mud pool; a mud overflow control valve and a three-way pipe are arranged in the drilling machine mud circulating pipeline; the three-way pipe is communicated with a waste