A segmented seal replacement construction method for a shield tail brush of a shield machine

By employing a triple water-stopping scheme of radial polyurethane grouting, thick grout filling of the tail shield, and double-liquid grout sealing ring, combined with segmented dismantling and brush fusion welding technology, the leakage and construction risks during the replacement of the shield tail brush of the tunnel boring machine were solved, achieving a highly efficient tail sealing effect and extended service life.

CN122304752APending Publication Date: 2026-06-30CHINA RAILWAY 20TH BUREAU GRP SOUTHERN ENG CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
CHINA RAILWAY 20TH BUREAU GRP SOUTHERN ENG CO LTD
Filing Date
2026-03-28
Publication Date
2026-06-30

AI Technical Summary

Technical Problem

Existing methods for replacing the tail brush of tunnel boring machines have problems such as poor water-stopping effect, high construction risk, and unstable sealing performance. In particular, leakage and safety accidents are prone to occur under complex geological conditions.

Method used

A triple sealing scheme is adopted, consisting of radial polyurethane grouting, thick grout filling of the tail shield, and a double-liquid grout sealing ring. Combined with segmented removal of the pipe segments and replacement of the tail shield brush piece by piece, a brush filament fusion welding process is used to ensure a sealing effect.

Benefits of technology

It achieves leak-free replacement of the tail brush, reduces the risk of water and sand inrush and shield retreat, and extends the service life of the tail brush.

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Abstract

This invention relates to the field of shield tunnel construction technology, specifically disclosing a method for replacing the segmented seal of the shield tail brush of a shield machine, including the following steps: S1: Ensure the surrounding environment is safe and controllable, with no visible leakage; S2: Inject polyurethane grout to fill the gap between the shield body and the soil; inject thick grout through the pre-reserved grouting holes of the segments; perform secondary grouting of the shield tail with two-liquid grout; S3: Use jacks to tighten and lock the unremoved segments; dismantle the segments in the order of "F block → L1 block → B1 block → B2 block → B3 block → B4 block → L2 block → re-dismantle F block". S4: Clean debris and old grease from the tail brush and sealing cavity in the area to be replaced; weld a new tail brush, remove a segment, and replace the corresponding tail brush; S5: Assemble the segments according to the original assembly points before removal, and tighten the bolts after assembly; apply grease to the surface of the tail brush by hand; S6: After confirming the tail sealing effect, segment connection quality, and equipment operating status, resume tunneling; maintain the tunneling machine in an upward-tilting posture during shutdown, and monitor the shield posture daily; regularly maintain the tunneling machine and its supporting equipment to ensure that tunneling can be resumed at any time. This invention solves the problems of poor water-stopping effect, high construction risk, and unstable sealing performance in existing methods.
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