Steel sheet pile cofferdam bottom rock-socketed anchoring method

The invention discloses a steel sheet pile cofferdam bottom rock-socketed anchoring method. The rock-socketed anchoring method comprises the following steps that 1, multiple pilot holes are drilled in an underwater batholith to form a completely closed continuous underwater batholith groove; 2, grouting pipes are welded to the inner sides of the middles of the groove bottoms of steel sheet piles, and the bottoms of the steel sheet piles are driven into broken rock slag of the continuous underwater batholith groove; 3, after the multiple steel sheet piles are connected to form a steel sheet pile wall, cement paste is injected into the grouting pipes. According to the rock-socketed anchoring method, the problem that the steel sheet piles cannot be directly driven into an underwater rock foundation is solved; through continuous grouting, the lower portions of the steel sheet piles can be effectively embedded and fixed, and the better seal effect is formed; the pilot hole construction and the abutment bored pile construction can be performed at the same time, and the time interval between procedures can be shortened; the excavated volume of rock under the continuous underwater batholith groove can be avoided or reduced, concrete is not needed to seal the bottom, and not only can the construction cost be reduced, but also the construction time can be saved.