The floating hoop structure is basically the same as the floating shoe, except that its lower end is a male buckle connected to the casing. The floating shoe body is made of alloy structural steel material, with the upper end connected to the casing and the lower end made of hemispherical cement or metal head to guide the casing down. It is equipped with a back pressure valve inside, which can be drilled with a PDC drill bit. The upper and lower channels of the valve are open when leaving the factory. When the casing is first placed, the liquid in the well has no resistance to the floating shoe. The pressure of the circulating mud will push the valve head down by one displacement, and the three flaps at the end of the valve stem will automatically fall off. After stopping the pump, the valve will press the valve seat upwards under the action of the spring, acting as a one-way valve. At this point, drilling fluid or cement slurry can be pumped in from top to bottom, but the liquid inside the valve casing or the annular space outside the casing cannot return.