High strength grouting method for single pile rock-socketed foundation of weakly weathered bed rock for offshore wind power

A high strength grouting method for a single pile rock-socketed foundation of a weakly weathered bed rock for offshore wind power, the method comprising the steps of:

• step S1, driving a steel casing (2) into an overburden layer (9) and leaning against a rock stratum (10), and performing excavation on the overburden layer (9) and the rock stratum (10) under the protection of the steel casing (2) to dig a pile hole, wherein an inner diameter of the pile hole corresponds to an outer diameter of the steel casing (2);
• step S2, hoisting a steel pipe pile (1) into the steel casing (2) and positioning the steel pipe pile (1) in the pile hole, wherein an annular cavity (11) is formed between the inner walls of the steel pipe pile (1) and the pile hole and the bottom of the steel casing (2);
• step S3, grouting a first grouting layer (4) into the bottom of a pipe hole of the steel pipe pile (1) for sealing the bottom of the steel pipe pile (1);
• step S4, grouting a second grouting layer (5), a third grouting layer (6), a fourth grouting layer (7) and a fifth grouting layer (8) successively into the annular cavity (11), wherein the second grouting layer (5) and the third grouting layer (6) are located in the rock stratum (10), the fourth grouting layer (7) and the fifth grouting layer (8) are located in the overburden layer (9), the second grouting layer (5) is made from an ultra-high strength cement-based grouting material, the third grouting layer (6) is made of a high strength cement-based grouting material, and the fourth grouting layer (7) is made of a common high strength cement-based grouting material;
• and
• step S5, pulling out the steel casing (2), wherein the steel pipe pile (1) is stably connected to the overburden layer (9) and the rock stratum (10) after a grouting solution is aged, to form a stable and reliable fan foundation.