Steel sheet pile supporting method for deep foundation pit

The invention discloses a steel sheet pile supporting method for a deep foundation pit. The steel sheet pile supporting method comprises the following steps: (1) preparing an inner support; (2) hoisting the overall inner support into the deep foundation pit with a hoisting machine, horizontally arranging the inner support, and fixing a sealing plate on one side of the inner support on a circuit purlin of steel sheet piles on one side of the deep foundation pit; (3) starting a telescopic device to adjust the inner support to a proper length, driving a wedge into a wedge-shaped gap groove to enable one end of the wedge to be propped against the sealing plate and the other end to be propped against a support plate of the inner support; (4) fixedly connecting the support plate with the circuit purlin of steel sheet piles on the opposite side of the sealing plate through bolts to enable the inner support to be horizontally arranged, and dismantling the telescopic device; and (5) removing the lifting hook of the ho