Cave plug flood discharging cave connected through open channel

The invention discloses a cave plug flood discharging cave connected through an open channel. The flood discharging cave comprises an inlet section, an open channel section, a vertical shaft section,a lower flat section, and cave plug sections which are sequentially arranged in the water flow direction. The open channel section is vertically communicated with the vertical shaft section; the vertical shaft section is vertically communicated with the lower flat section; the number of the cave plug sections is multiple; and the cave plug sections are closely connected with one another. The connecting mode, the structure and the arrangement mode of a cave plug energy dissipater are improved, the dynamic load of a bottom plate of the vertical shaft section can be reduced, and air in a verticalshaft can be exhausted easily. During flood discharging, water flow in a reservoir flows into the vertical shaft from the open channel and is changed into pressure flow from non-pressure flow, so that the reduction of the hyd