Deep well soil taking device in underwater pile and construction method thereof

The invention relates to a deep well soil taking device in an underwater pile and a construction method thereof. The deep well soil taking device in the underwater pile and the construction method thereof are particularly suitable for in-pipe dredging and soil taking for a guide pipe frame and an independent pile pipe of an offshore operation platform and can also be applied to in-pipe dredging and soil taking for underwater pile pipes in rivers and lakes, and the construction efficiency can be improved. The device comprises a high-pressure centrifugal pump, a double-way composite pipe is provided with an inner pipe and an outer pipe, and the two ends of each of the inner pipe and the outer pipe are correspondingly connected with an inner pipe and an outer pipe of a suction and drainage assembly as well as an inner pipe and an outer pipe of a machine frame upper flange of a soil breaking machine frame; the suction and discharge assembly is provided with a water inlet and a slurry discharge opening, the slurry