TWI835099B

The present invention relates to a horizontal compartment system and its construction method, which are auxiliary necessary operation items for a deep ditch for the predecessor operations of a continuous wall project of a new building when an old foundation of a building structure is to be renewed. The construction steps include: knocking out an existing raft base layer and an existing floor level at a predetermined position; constructing a plurality of outer guide ditch walls, a plurality of inner guide ditch walls and a plurality of horizontal compartments at the same predetermined position and knocking out existing beam components, wherein the plurality of outer guide ditch walls, the plurality of inner guide ditch walls and the plurality of horizontal compartments are connected to each other. The above steps are repeated to another upper floors in sequence until to the ground floor to form the horizontal compartment system that effectively and stably supports the outer guide ditch walls and the inner guid