Prefabrication and installation method of detachable steel protection tube device and underwater connection beam

The invention relates to the technical field of construction, in particular to a prefabrication and installation method of a detachable steel protection tube device and an underwater connection beam. The prefabrication and installation method is suitable for water facing region bridge pile foundation and underwater connection beam construction. The method specifically includes the steps that the detachable protection tube device is manufactured, and a crane is adopted for assembling upper protection tubes, middle protection tubes and lower protection tubes into a whole; the steel protection tubes are buried according to pile position surveying and setting-out positions; a drilling machine is arranged in place, and hole forming, hole cleaning and underwater concrete filling piling are conducted; upper mud or cement slurry is pumped out through a pump, and after the strength of concrete reaches 5 MPa, ultrahigh portions are manually chiseled out; and after a whole pile foundation is formed, vertical flange bolts between first vertical detachment blocks and second detachment blocks and between the first vertical detachment blocks and third detachment blocks and second radial flange bolts between the middle protection tubes and the lower protection tubes are loosened. Compared with the prior art, the prefabrication and installation method is simple in structure, flexible in operation, safe, reliable, economical, efficient and suitable for construction of pile foundations in water areas with high environmental protection requirements. Mud collection is greatly facilitated, the construction efficiency is improved, and secondary pile extension is avoided.