Method for injecting expansion polyurethane mixture to repair sedimentation terrace and reinforce foundation

The invention relates to a method for injecting an expansion polyurethane mixture to repair a sedimentation terrace and reinforce a foundation. The method includes: determining an injection hole needing to be drilled according to the reconnaissance situation of underground soil and underground barriers of a section needing to be repaired and reinforced; using an injection device to inject the expansion polyurethane mixture to the injection hole; injecting the expansion polyurethane mixture again after the expansion polyurethane mixture is solidified completely, and completing filling of a gap between the terrace and foundation soil; and filling cracks of the terrace with a rapid hardening polymeric material to complete repairing and reinforcement of the terrace. The method provides a new scheme for repairing and reinforcing industrial building terraces, is simple and easy to operate, has significant advantages in economic and technical norms, and is a clean, environment-friendly, rapid, damage-free, interfere