Method for sealing post-cast strip in foundation with no gap

A method for sealing a post-cast strip in a foundation with no gap includes the following steps: mounting steel plates, horizontal pipes and vertical pipes cooperatively layer by layer in a post-cast strip, respectively, such that the upper open end of each vertical pipe protrudes from the ground through the post-cast strip; pouring grout into the post-cast strip from the top of the post-cast strip after the end of the settlement of the foundation, and carrying out high-pressure grouting into the vertical pipe using grouting equipment simultaneously; delivering the sealing grout poured into the vertical pipe to the horizontal pipes, such that the sealing grout overflows from the grout outlets of the horizontal pipes to densely fill up existing gaps; and cutting off the portion of the vertical pipe above the ground after the post-cast strip is completely sealed, and levelling the top of the cut-off vertical pipe with concrete.