Fixing method of locking foot of steel arch frame for primary support of tunnel

Abstract

The invention relates to a tunnel primary support steel arch frame lock foot fixing method. The method comprises the following steps that 1, a seamless steel pipe is machined to be the fixed length, one end of the seamless steel pipe is machined to be sharp, the other end of the seamless steel pipe is machined to be an oblique angle of 30 degrees, grouting holes are formed in the pipe wall in the shape of quincunx, and then a locking anchor pipe is obtained; 2, a positioning plate is adopted for machining a pair of square steel frame positioning holes on a web of a profile steel frame; 3, screw-thread steel is adopted for being prepared into U-shaped clamp rings; 4, a drill pipe drills holes in the direction of steel frame positioning holes, and after the holes reach the designed depth, installation is conducted in place; 5, the two U-shaped clamp rings oppositely penetrate through the steel frame positioning holes and are clamped on the locking anchor pipe, and U-shaped clamp ring arc welding connection surface, the locking anchor pipe and a U-shaped clamp ring arc welding connection surface are formed through welding separately; 6, grouting is conducted after connection of a grouting pipe and the locking anchor pipe, and finally a grout stop valve is installed. Accordingly, the fixation of the locking anchor pipe on the tunnel primary support section steel arch frame can be effectively improved, tunnel primary support sinking and deformation are prevented, and the safety factor of tunnel construction is strengthened.

Description

technical field [0001] The invention relates to the technical field of tunnel construction in highway engineering and railway engineering, in particular to a locking foot fixing method of a steel arch frame for primary support of tunnels. Background technique [0002] In the traditional construction technology of lock-foot anchor tube, the fixing bars of the lock-foot anchor tube are fixed on the outer edge of the arch frame, which cannot be well connected with the lock-foot anchor tube, and the lock-foot anchor tube needs to be pre-installed for the initial support of the outer edge of the steel arch frame. If the welded joint is left, it is easy to scratch and puncture the waterproof board of the subsequent tunnel construction. Before the construction of the waterproof board, the reserved locking foot anchor pipe head needs to be cleaned, which is difficult, labor-intensive and time-consuming. In addition, since the fixing ribs of the lock-foot anchor tubes are completed b...

AI Technical Summary

Problems solved by technology

[0002] In the traditional construction technology of lock-foot anchor tube, the fixing bars of the lock-foot anchor tube are fixed on the outer edge of the arch frame, which cannot be well connected with the lock-foot anchor tube, and the lock-foot anchor tube needs to be pre-installed for the initial support of the outer edge of the steel arch frame. If the welding head is left, it is easy to scratch and puncture the waterproof board of the subsequent construction of the tunnel. Before the construction of the waterproof board, it is necessary to clean up the reserved locking foot anchor pipe head, which is difficult and time-consuming

In addition, since the fixing ribs of the lock-foot anchor tubes are completed by arc welding on the outer edge of the arch, the arch is under the stress of the surrounding rock, and the welded parts of the fixing ribs are easy to de-solder after the lock-foot anchor tubes are stressed. Breakage and voiding become the weak link of the initial support of the tunnel, and the locking foot anchor pipe cannot play its due role, causing the initial support of the tunnel to sink and deform

The angle of the locking feet should not be controlled, and the angle of the outer pins is insufficient (<30º), which weakens the anchoring effect of the locking feet

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