A construction method of a large-diameter rock-socketed anti-floating bolt and a drilling tool used in the method

Abstract

The invention provides a construction method for a large-diameter rock-socketed anti-floating bolt and a drilling tool used for the method. The construction method adopts a deep-layer mixing pile driver, the drill bit adopts an air down-the-hole hammer, and the inner cavity of the drill pipe is divided into a gas transmission channel and a grouting channel along the length direction of the drill pipe; the high-compression air is used to drive the down-the-hole hammer Carry out drilling, when drilling to the bottom of the hole, keep the down-the-hole hammer working continuously, stay at the bottom of the hole for 2 to 4 minutes, and inject chemical mud through the grouting channel in the drill pipe, then lift the drill pipe upwards, and continue to inject Chemical mud, after the drill pipe is lifted to the ground, the bolt is quickly lowered into the borehole, and then cement slurry is injected to replace most of the chemical mud. After the cement slurry is initially set, the second splitting grouting is performed to complete the bolt the embedding process. The invention has simple construction, can solve the construction of large-diameter rock-socketed anti-floating bolts in water-rich granite areas, and has high construction efficiency, low cost and reasonable management.

Description

technical field [0001] The invention relates to the technical field of engineering, in particular to a method for constructing a large-diameter rock-socketed anti-floating bolt with a diameter of 220 mm used in water-rich granite areas and a drilling tool used in the method. Background technique [0002] With the emergence of more and more deep foundation pit projects, in order to meet the anti-floating requirements, the application of anti-floating anchors is becoming more and more common. In granite areas with abundant groundwater, the construction diameter is larger The existing rock-socketed anti-floating bolts are very difficult, inefficient and costly in terms of current construction techniques. The reasons are as follows: 1. Abundant groundwater, coupled with rich bedrock fissures in the fragmented strongly weathered granite, so the groundwater supply is sufficient during the construction process, and there is continuous water in the hole; 2. Anti-floating bolts mus...

AI Technical Summary

Problems solved by technology

In granite areas with abundant groundwater, the construction diameter is larger The rock-socketed anti-floating bolts are very difficult, inefficient and costly as far as the current construction technology is concerned.

The reasons are as follows: 1. Abundant groundwater, coupled with rich bedrock fissures in the fragmented strongly weathered granite, so the groundwater supply is sufficient during the construction process, and there is continuous water in the hole; 2. Anti-floating bolts must be inserted into the weathered bedrock, Generally, a down-the-hole hammer is used to break the rock, but when the airflow of the down-the-hole hammer cuts the bedrock, it will also return to drive the groundwater to disturb the hole wall, making the hole wall unstable, resulting in excessively thick sediment, and even hole collapse. The rod is very easy to be buried; 3. To solve the disturbance of the hole wall in 2, it is usually drilled with a full casing at present, but due to the large diameter of the borehole It is necessary to use Yutong or German Bauer series rock bolt rigs, and custom-made casings and fixtures; although this can solve the problem of hole collapse, but because the weight of the custom-made single-section casing is heavy, it is very laborious for workers to operate, and the efficiency is low. Can not meet the production and economic requirements

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