Plugging method of dewatering well for ultra-deep foundation pit under water-rich soft foundation condition

The invention discloses the technical field of dewatering well plugging, and particularly relates to a dewatering well plugging method for an ultra-deep foundation pit under the water-rich soft foundation condition. After the water pump in the dewatering well is taken out, the tray and the sealing material are quickly subjected to compression joint sealing treatment through the hooking piece made of field waste steel, glue is injected between the dewatering well and the steel sleeve, the second sealing body is thoroughly pressed on the inner wall of the dewatering well after glue injection, and then the dewatering well is blocked. And finally, the top of the steel sleeve is fully filled with micro-expansive concrete, then full welding and rust prevention treatment are conducted, finally, the dewatering well is thoroughly plugged, foundation construction rich in confined water and large in water return amount can be eliminated, and for the plugging process of the dewatering well in a structural bottom plate ri