Hoisting and positioning construction method for sounding pipe of foundation pit top-down method cast-in-place pile

The invention relates to the technical field of foundation pit cast-in-place piles, and discloses a hoisting and positioning construction method for a sounding pipe of a foundation pit top-down method cast-in-place pile. The hoisting and positioning construction method comprises the following construction steps that 1) a pile hole is rotatably dug; 2) a bottom sounding pipe is fixed to a main reinforcement of a reinforcement cage, and the reinforcement cage is lowered into the pile hole in a suspended mode; 3) a lengthened sounding pipe is connected to a lengthened reinforcement, the lengthened reinforcement is fixedly connected with the main reinforcement, and the lengthened sounding pipe is fixedly connected and communicates with the bottom sounding pipe; 4) the reinforcement cage is lowered to the bottom of the pile hole, and the top of the lengthened sounding pipe is exposed above the pile hole; and 5) concrete is poured into the pile hole, and a cast-in-place pile section is formed on the lower portion o