The steel joint structure is composed of connecting steel plates and partitions. Some partitions are reformed. The partitions are changed into pure "I" type structure (removing the original small stiffeners). The upper flange plate is outer ring connecting steel plate, the web plate is partition plate, the lower flange plate is inner ring connecting steel plate, and a cushion plate is added at the top of the upper flange.
For the whole circle of steel joints, the partition we reconstructed involves four parts of the top wall area, two parts of the side wall area and seven parts of the bottom wall area. The partition structure of the reconstructed partition was welded before the temporary bracing pipe was demolished (or partially demolished) to reinforce the pushing trabecular, so as to avoid the failure of water stop in the combined chamber.