Fabricated foundation pit supporting system based on jet grouting technology and steel pipe piles and construction method

The invention relates to an assembly type foundation pit supporting system based on a jet grouting technology and steel pipe piles and a construction method. In a foundation pit support and water stop structure, an underground diaphragm wall has the problems of high manufacturing cost and long construction period, and common secant piles generally have the problem of forking between deep piles of a foundation pit. The system comprises jet grouting piles, tooth-shaped crown beams and miniature steel pipe piles. The jet grouting piles are secant piles and are vertically arranged in rows on the outer side of the foundation pit; the tooth-shaped top beams are located on the pile tops of the jet grouting piles and are sequentially spliced in an engaged mode. The miniature steel pipe piles are inserted into the tooth-shaped crown beams and the jet grouting piles, and the miniature steel pipe piles and the jet grouting piles are coaxially arranged. The system is a foundation pit support structure and also has the wa