Method for conducting grouting construction at back of pile bottom of cast-in-place pile

Abstract

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.

Description

technical field [0001] The invention relates to a construction method for building foundation piles, in particular to a post-grouting construction method for pile bottoms of cast-in-place piles. Background technique [0002] Cast-in-situ piles have been widely used in construction projects because of their high bearing capacity and strong applicability, but the defects of cast-in-place piles will also cause insufficient bearing capacity of single piles due to certain reasons. Post-grouting technology is an auxiliary process for the construction of cast-in-place piles, which can effectively make up for the defects of cast-in-place piles and improve the bearing capacity of single piles. Post-grouting at the bottom of cast-in-place pile means: when the concrete of the pile body reaches a certain strength after the concrete pouring pile is formed, the cement slurry is injected into the bottom of the pile under pressure through the post-grouting equipment, and through the permeat...

AI Technical Summary

Problems solved by technology

[0004] However, since the grouting pipe and the steel cage are fixed together, it is easy to drive the grouting pipe to float up due to the floating of the steel cage, which affects the smooth progress of grouting and causes grouting failure; moreover, after the concrete pouring pile is piled, The outside of the grouting injection head is often covered with solidified cement slurry, so that the grouting check valve is not easy to open. Before each round of grouting, high-pressure water with a pressure of up to 8-10 MPa is needed to press the grouting sheet on the grouting injection head. Directional valve, and the grouting injection head is often blocked, making it impossible to grout smoothly

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