Small-diameter hard rock pipe-jacking machine suitable for complex strata

The invention provides a small-diameter hard rock pipe-jacking machine suitable for complex strata. The small-diameter hard rock pipe-jacking machine can be suitable for soft and hard alternated strata and transitional strata. The small-diameter hard rock pipe-jacking machine comprises a cutter head at the front end, a front shield and a driving system, the front shield is connected with a tail shield through a deviation rectifying system, the rear end of the tail shield is connected with a pipe joint, a shield body is internally provided with a slurry circulation system, the driving system is connected with the cutter head through a twisted leg, a conical ring is connected with a front shield partition plate, the twisted leg and the conical ring are arranged in a slurry bin which is formed between the cutter head and the front shield partition plate, an air cushion bin is formed in the front shield, and a communicating valve is arranged between the slurry bin and the air cushion bin; a slurry bin slurry discharging pipe is connected to the slurry bin, an air cushion bin slurry discharging pipe is connected to the air cushion bin, and the slurry bin slurry discharging pipe and the air cushion bin slurry discharging pipe are connected with the slurry circulation system. The small-diameter hard rock pipe-jacking machine can be suitable for single strata of soft soil, soft rock, hard rock and the like and the soft and hard alternated strata and the transitional strata, and two tunneling modes of a slurry balance tunneling mode and an air cushion assisted slurry balance tunneling mode can be achieved according to different strata.