A method for conducting grouting construction at the back of the
pile bottom of a cast-in-place
pile sequentially includes the following steps: (1) manufacturing and arranging a grouting
pipe which comprises a plurality of grouting steel
pipe sections sequentially connected from top to bottom with the lower end of the lowest grouting steel
pipe section connected with a grouting spraying
nozzle; (2) assembling a grouting
station and a
slurry transportation pipeline; (3) grouting. The method is characterized in that the grouting spraying
nozzle used in the step (1) comprises a
slurry spraying pipe body, a
slurry inlet is formed in the upper end of the slurry spraying pipe body, a plurality of slurry discharging holes are formed in the lateral wall of the slurry spraying pipe body, a grouting one-way valve is installed on the slurry discharging holes, a sand wrapping device is arranged on the outside of the slurry spraying pipe body, a sand
isolation layer is arranged between the sand wrapping device and the outer side of the slurry spraying pipe body, and the sand
isolation layer covers the grouting one-way valve. When the grouting spraying
nozzle reaches the bottom of a
pile hole, and the portion of the upper end of the grouting pipe higher than the ground reaches preset height, the upper end of the grouting pipe is fixedly connected with a protection
barrel at the top of the pile hole. By means of the method, smooth grouting can be achieved, grouting quality is ensured, and success ratio is ensured.