Shield tunnel prefabricated tunnel segment lining back stratum grouting device

The invention provides a shield tunnel prefabricated tunnel segment lining back stratum grouting device. Through the device, a gap formed between a shield tunnel segment lining ring and a stratum can be subjected to repeated grouting for many times, and in addition, the problems of grouting holes, blocky grouting regions and the like at the back of the shield tunnel segment lining ring in the shield construction process can be effectively solved. The device comprises a grouting sleeve, a multi-way connecting pipe and a slurry discharge pipe, wherein the grouting sleeve consists of an extending section and an internal screw thread section, and is embedded in the prefabricated tunnel segment lining, an outer end opening of the internal screw thread section is communicated with the inner side surface of a prefabricated tunnel segment lining tunnel, the extending section is connected with a main pipe of the multi-way connecting pipe, the main pipe of the multi-way connecting pipe is connected with the extending section of the grouting sleeve, branch pipes of the multi-way connecting pipe are connected with the grouting pipe, a slurry discharge hole or a slurry discharge belt is arranged on the pipe wall of the slurry discharge pipe, and is embedded in the outer side of the prefabricated tunnel segment lining in a radial shape or a lattice shape like a Chinese character 'tian', one end of the slurry discharge pipe is connected with the branch pipes of the multi-way connecting pipe, and the other end of the slurry discharge pipe is sealed or connected.