Down-type deep drain hole interior protective device adaptive to deformation and installing method

The invention discloses a down-type deep drain hole interior protective device adaptive to deformation and an installing method. The down-type deep drain hole interior protective device adaptive to deformation comprises a water drain section (1), a deformation-adaptive section (2) and a water guide section (3) which are connected in a sleeved mode from top to bottom. A U-PVC plastic hard pipe (4),geotechnical cloth (5) and wall holes (6) are arranged in the water drain section (1). The U-PVC plastic hard pipe (4) is hollow, and the wall holes (6) are formed annularly in the pipe wall. The outer surface of the U-PVC plastic hard pipe (4) is wrapped by the geotechnical cloth (5). A hollow PVC steel wire hose (8) is arranged in the deformation-adaptive section (2) and arranged in the axis direction. The U-PVC plastic hard pipe (4) and a lead wire mesh (9) are arranged in the water guide section (3). The tail of the U-PVC plastic hard pipe (4) is wrapped by the lead wire mesh (9). The down-type deep drain hole in